Blower Motor Runs Then Stops


A constantly running furnace that doesn't shut off can be a sign of a needed repair. Because the blower fan is an expensive part. In some cars, a failed blower motor resistor can cause a heater fan to stop working completely. Another Blower motor problem, works fine, then hit a bump, doesn't If it works, then I hit a bump, it stops. About 45 - 60 minutes into my drive the blower stops blowing. Randomly, the Front Blower Motor will stop moving cold air. This is an anticipator function, designed to keep the temperature from overshooting the set point. Cool air is sent by the blower into the heat exchanger and warmed before entering the plenum and then sent throughout your home by the supply ducts. The experts at Snow Blowers Direct have written a guide on how to start a gas snow blower. Then the motor may not ever get high enough in speed to open the start winding. Blower wasn't operating in the different speeds. The blower motor resistor is located right at the blower motor under the passenger side dash board. I don't think it is the fuse (all the 50's look OK) - especially since the motor came back on - until my wife turned the switch off - then it never came back on again. The following assumes your blower motor is failing on all 4 speed positions. Blower does not start. and shuts down correctly. Replace the connector and add a extra ground from the blower motor. And finally, since the cabin/charcoal filter sits right on top of the blower assembly, I thought a simple relabel of the title would suffice. Now I have the first 3 speeds working but the motor still doesn't blow on high. A dirty filter is the #1 reason for your furnace to stop working due to overheating. I have gotten the tub to cycle and heat up fine, but when the motor is running on high, the motor itself shuts off after a few seconds of running. Choosing A Blower Motor. Ok, if you've verified that the controls and fan are good, take a break for a diet soda, and then we'll see if the evaporator coil or ducting are the cause of your air conditioning freezing problem. mode selector. I don't know the brand or model, but the circuit board is a spabuilders one and there's a date of 07/2005 on the tub itself, so it is quite old. Working on a 2014 Ram Laramie Longhorn 2500 with auto a/c temp function. blower stays running for another 15 minutes. This could cause the blower motor to become inoperative. The Indoor Blower Is Running For A Short Time, Then It Stops. Also last few days when the blower has been running for a while, it just quits and a few hours later, it will work again. I don't believe the digital climate control units use a blower motor relay. Here's my 2 cents, but it's based on my old 1990 1500. How To: Troubleshoot a heater blower motor Blower HVAC Blower works then stops for days , then suddenly Starts up again and runs for days, Then after a some. Motor sounded like it was trying to run as if low voltage. The blower motor on my 2000 v8 dodge Dakota would work normal and then slow down and almost stop it would do this the whole time the heater was running Is the resistor shot or the blower motor Most likely blower motor. How do I test the blower motor to make sure it is defective? It has a strange three prong plug with two round prongs and one flat. Blower: Runs For A While Then Dies. If the system previously had a leak that caused the evap to freeze up, that could have caused the blower motor fail. The blower control could be incorrectly set, or the limit switch on the Lennox Elite Series furnace unit itself isn't set. I won't be able to change the blower speed but it'll do for now. Finally tapped on blower motor and it ran. Symptoms of a Bad or Failing Blower Motor Relay. A capacitor that is malfunctioning or failing can cause the fan's motor to slow down and/or overheat. 5 minutes the blower suddenly stops even though the burners remain lit. Symptom: Blower motor only working on certain settings. With cooling off or on, I can turn the fan switch to "ON" from the t-stat, and the same thing happens (starts after a minute, then shuts off after 30 seconds). Starts well and runs for a while and then suddenly shuts off as if a switch was thrown. If none of these troubleshooting steps work, call a professional technician, as the. If the blower motor won't stop running regardless of the actual temperature of the home, there are two possible causes. That's where Repair Clinic comes in. 5 minutes the blower suddenly stops even though the burners remain lit. Likely the motor or. It happened on three or four occasions and never happened again. Then grab the other end of the shaft with a pump pliers and turn it to break it loose (Photo 2). If 1-4 work and 5 doesn't, check the 30 amp fuse (thats what it is on my 2001) under the hood in the fuse panel (Climate Control fuse). If the motor runs but the blower doesn't move air, the belt that connects the two probably has broken. ) Insert the Safety Ignition Key. Most fans are energized by a fan relay. What is a run capacitor used for? A motor run capacitor is used to continuously adjust current or phase shift to a motor's windings in an effort to optimise the motors torque and efficiency performance. This happens the entire time the system is running. cars with climate control have to run the blower motor almost constantly in different speeds to keep the inside tempreture constant so the motor does not last as long as cars without climate control. In, fact, this occurrence happened to him not once, not twice, but. With out being able to find the make or model no of my furnace it is total elect and is not a heat pump, what could cause the blower motor to slow down. Same issue!!! Ignition switch in acc or run position & fan switch off - fan off. An inducer motor and blower assembly is definitely one of those parts you don't think about until something has gone wrong with it. Turn off and lock out power to the motor. I replaced the blower motor & squirrel cage; then all three relays and the thermositor and still the same issue. The inside (fan coil) blower continued to run despite that the condensing unit was not. The two immediate ways to address this issue is to learn to remember to cycle the switches in the above manner or replace the aged blower motor with a new one. I have not had time to check it out yet but I was wondering if this an issue with blower motor itself or the resistor or switch or whatever it is called. What can happen when a blower motor resistor goes bad is that the motor will run and then suddenly stop running on a regular basis. So I put the motor back in place and hook the purple positive back up and then ran a jumper from the negative terminal on the motor to a ground under the dash. Hey guys, Do you have any kind of Darwin stupidity award? If so I'd like to nominate myself :-) I'm sorry the following doesn't have pictures, it's. My 4450 ac blower motor worked fine all day yesterday until the last 2 hours and then it shut off. Frigidair model # AE06000ES2 My dryer runs for 10 minutes then it stops, All the leds are are on some of them blinking, Display has an AD. Other posters have reported that the blower motor has failed. I had this problem and had to change the blower motor. A motor has four leads out of it: two red and two black. Blower motor began running on high and will not shut off even when truck is turned off. Replace the connector and add a extra ground from the blower motor. Eventually, after many attempts the blower fan will kick on and the AC will begin to cool again then rinse and repeat all day. If the system previously had a leak that caused the evap to freeze up, that could have caused the blower motor fail. Turns out the blower motor was going bad, the bushings were bad causing the internal coils to rub resulting in a intermittent issue with the blower motor stalling. Choosing A Blower Motor. Same issue!!! Ignition switch in acc or run position & fan switch off - fan off. Sometimes the motor is on for only a split second. no noise of it even trying. The relay is located in the passenger compartment and is attached to the stop lamp switch bracket (Figure 1). Did cold weather cause my Jeep's heater fan to stop blowing and then start again later? No blower, no heat, no front defrost, nothing. I couldn't tell where that ground wire leads to see if it worked its way loose. Messages: 108 Page 2 of 8. It will restart if you press cancel first, it does not seem to be heating, the air coming out iis cool. The motor has a shaft running through the center of it with the shaft on the left side driving the main furnace blower and the shaft on the right side driving the combustion blower. Symptom: Blower motor only working on certain settings. If the blower doesn't start, then the problem could be a fuse inside the furnace, a loose connection or a bad blower motor. Solved: Craftsman leaf blower only runs at full throttle and half choke Discussion in ' Do It Yourself (Not Computer-Related) ' started by lexmarks567 , Aug 12, 2006. it then started and stopped about a dozen times and then staid off. It felt a little stiff too me. If there is no voltage there while you hear the noise, I suspect the vent (inducer) motor is the source of the noise. The blower keeps working after I hit the dash I turn the car off then the next time I start it (10 mins later) and the blower does not work I have to hit dash again. Never allow anyone, especially children, to operate the snow blower without proper instruction. I have blower on high speed only. The only way I can stop the fan is if I turn the vehicle off, then press OFF then restart the vehicle. The blower spins up, runs at a low speed for a few seconds, and turn off again. I have a few questions: #1) Is the blower regulator the problem? #2) Can I replace it easily myself if I buy one on-line?. Just as an FYI, the retail price of the blower motor control processor is. So, if your blower is turning on/off during a heating cycle or after the call for heat stops, you have a problem. It seems the blower motor does not work. After we help you figure out why your furnace blower starts then stops, we'll show you how to fix it. I have an older Buck Stove fireplace insert and it has a blower motor. So I replaced that and it worked and we’ve run a few loads thru no problem. The blower motor is running, just stops blowing cold air threw the dash vents. These post are my personal posting and have nothing to do with the FORDF150 site. It sometimes run for a few seconds and then stop. Doesn’t run Replace the blo er. It would run, kinda low speed, for about 30 seconds and then I would hear a click and it would. NO burning or other smells coming from the AC unit. This would be normal. Heater/ Ac Intermittent Blower Motor shutting off and not coming back on until you press OFF then Auto again and it would do the same thing. Then try removing it. Blower motor won't shut off - help!! There is a thread from a couple of days ago, someome had this same thing with the blower running all the time. Is the motor really hot to the touch when it shuts off? permalink;. The second problem SOUNDS like-- The Infamous Blower Motor problem. A common symptom of a failing final stage unit is the blower motor not operating in accordance to how the controls are set, as if the blower "had a mind of its own". Since the blower is already spinning, the motor can start without a start capacitor. Just as an FYI, the retail price of the blower motor control processor is. Normally, when this engine burns gas, the vapors and heated gases are vented away, so the engine can stay cool enough to keep running. If you start at the blower motor, and check resistance in the circuit, you will find the problem in no time. You will first need to prepare the leaf blower and then make an idle speed adjustment. I have a 2005 TR4 and for the last two weeks my AC will stop blowing air for a day or so and then it start working again. The blower control could be incorrectly set, or the limit switch on the Lennox Elite Series furnace unit itself isn't set. Then it goes. If so I suspect that there is an earth fault on one of the wires connected to either pin 4 or 5 of the resistor. It has a 2 position switch to run all the time or on a thermostat. Re: blower fan works for a whilethen quits?? Updated 7:05pm Eastern on 8/7/07 While this is not a good fix you might have someone that does electrical work rig up a power cord to the blower motor (If the motor is good) and plug it in. I would shut the breaker off and then it would be okay. 2003 Honda CRVwhen changing blower speed from low to high, it hesitates or stops altogether. The blower motor will not work on an engine restart unless the a/c controls were switched off before the ignition was cycled off and back on after the engine is running again. Did cold weather cause my Jeep's heater fan to stop blowing and then start again later? No blower, no heat, no front defrost, nothing. I took the cover off I see that the blower motor itself is a ways away from where I hit the dash. In most cases like this, the run capacitor needs to be replaced. Only happens when on #3, so I was thinking if it's the Blower then why doesnt it stop when I have it on #2 and High Fan? Any Ideas?. Turn off and lock out power to the motor. Looks like an X13 motor. In a gas furnace, the blower will continue to run if the fan switch on the thermostat is set to any setting other than auto. A/C system can be turned off and on multiple times, but the front blower fails to respond. Last year my blower motor kept going in and out so I took the the ground piece that was bolted to the fender on the right side and sanded it down like most people said to do and I put it back on and it worked for a year well Im starting to have the same problem again where you turn the knob to 0 and the ac light is still on like there is a ground issue. 20 Seconds is the give away here, telling me you have a single phase motor. 5 seonds and stops, then starts again DC Motor only runs. The car manual gives location of all fuses and what they are but not the relays. Same thing when going from high to low. My leaf blower starts, runs for 5-6 minutes then stalls out. My Snowblower stops running after about 20 minutes of use??? I have a 2 cycle snowblower and it's only about 2 years old. heater blower failure common on the 2000 jetta tdi? can get a used one at auto wrecker $95 or vw $340. every once in a while it will work correctly for a few hrs then starts on and off. Turn off your A/C, remove the INSIDE shroud. My central AC unit decided to stop on the hottest day of the year. The motor will start when it has cooled down, then stops running as described above. The type of carnage I found with the connector and resistor signaled me to pull out the blower motor and take a look at it. Common applications of split phase motors include: fans, blowers, office machines and tools such as small saws or drill presses where the load is applied after the motor has obtained its operating speed. Drove car home last night. Chances are your RUN winding is out of order. Turns out the blower motor was going bad, the bushings were bad causing the internal coils to rub resulting in a intermittent issue with the blower motor stalling. If the blower shuts off replace the 160° F (71°C) fan temperature sensor. I have a 2007 Camry LE 4 cylinder with manual climate control. The Indoor Blower Is Running For A Short Time, Then It Stops. The torque to drive the motor of your electric fan comes from the magnetic field induced in the motor coils when electricity passes through the coils. Just wanted to share my experience with the intermittent running blower. Had 2 occasions when the blower motor just started running on high since then and wiggled the plug. In some cars, a failed blower motor resistor can cause a heater fan to stop working completely. Replacing it is an easy fix. Only one of the switches on the defroster levers work to start the engine compartment blower fan and it does work, but usually needs a bump from a jack handle or similar then will run with no noise. When the temp raises again the outside central unit kicks on like normal, but the blower inside will act like its starting then stop , and it will keep trying to do that every so often while the outside unit keeps running. Used OEM auto parts. If the blower motor needs replacement, it is from under the passenger side foot area. I have experienced this with a Q7 fan blower. Indoor air pollution is a real thing, and you may be surprised to learn that the air inside your home is often more polluted. The blower keeps working after I hit the dash I turn the car off then the next time I start it (10 mins later) and the blower does not work I have to hit dash again. On several ocassions my AC blower has just shut off. Heater Blower Motor Switch Resistor for all 1965-1966 Mustangs and all 1967 Mustangs without Air Conditioning. It has an SF-25 furnace. If there is no voltage there while you hear the noise, I suspect the vent (inducer) motor is the source of the noise. 2005 Silverado Crew Cab. If I dare put the climate control thing back to life -> blower motor goes full blast and cannot be stopped unless I turn off the vehicle. If the blower motor won't stop running regardless of the actual temperature of the home, there are two possible causes. [HVAC] Runs for a few seconds then stops. (See: Definition: f-stops). Blower Motor Slows Down After a Minute or so. Air Conditioner Blower Motor Prices and Replacement Procedure. Turn off your A/C, remove the INSIDE shroud. Problems that you can easily repair on the leaf blower include the engine not starting and the engine not idling or dying when at full throttle. Motor starts on one pull with no choke and runs excellent. I had this looked at by a local spa shop and the technician they sent out thought it was a pressure switch that was stuck open (or closed). Car A/C Stops Cooling or Working After a Few Minutes the idea of a relay to run 12v directly has been floated. Does the blower motor run with the switch in the OFF position? If you leave the blower motor switched continually on you may not notice this. Then use a garden hose and towel to spray it clean with scrubbing bubbles. 5 is the only speed that is affected if that fuse is blown. Run capacitors create the rotating magnetic field in your system's condenser fan. Sometimes there can be an issue with the blower motor control module which can be fixed by installing a few used auto parts instead of replacing the whole blower motor. The blower motor resistor is around 30 to 50 dollars and is readily available at your local auto parts store. heater blower failure common on the 2000 jetta tdi? can get a used one at auto wrecker $95 or vw $340. Remove the belt guard. In the case of air conditioners, capacitors are used to kick-start the compressor, the outdoor fan motor, and the blower fan (indoor unit fan). Your blower motor controls are much more complex than you would imagine when you look at them, which is why there are a number of things that can go wrong. Resistor looked burnt and cracked so I'd also replaced it. As the relay is the switch that supplies current to the blower motor, if it fails internally, then power will be cut off from the blower motor circuit, causing the motor to no longer function or. These have been issues with the failures ranging from locked/no spin at all, running at slow speed, and runs normally then stops. Eventually, after many attempts the blower fan will kick on and the AC will begin to cool again then rinse and repeat all day. Fuse, switch, motor, resistor bank, and wires. Funny thing is when I put it to on instead of auto the blower starts up just fine. I am new to the forum so bear with me here. Blower wasn't operating in the different speeds. If I put my climate control to OFF, the blower motor keeps going. If the engine on your blower runs then dies, you might need to check the tank vent, ignition coil, or gas cap. Solved: Craftsman leaf blower only runs at full throttle and half choke Discussion in ' Do It Yourself (Not Computer-Related) ' started by lexmarks567 , Aug 12, 2006. Turns out the blower motor was going bad, the bushings were bad causing the internal coils to rub resulting in a intermittent issue with the blower motor stalling. There are two common types of motor capacitors, run capacitors and start capacitors. These have been issues with the failures ranging from locked/no spin at all, running at slow speed, and runs normally then stops. Starts and stops itself. The photograph above shows the scene as shot in the right hand panel. I replaced the fan and limit control. If I wait 10-15 minutes it will start, and stop again. In this video we're going to show you how to replace the air conditioning and heater blower motor. If your air conditioner is starting up without a problem but then doesn't seem to run as well as it used to, then the run capacitor is most likely your problem. Messages: 108 Page 2 of 8. I forget how to test these relay switch, been a while since I've used my old DMM. Change the cabin filter while you have it opened up. Finally, I convinced myself that the motor by the passenger's right foot was the blower motor. I couldn't tell where that ground wire leads to see if it worked its way loose. mode selector. I assume you are having a problem with the engine stalling after it starts. I have to do this also. You will first need to prepare the leaf blower and then make an idle speed adjustment. On pump leaded it ran 10. With the blower turned on and the a/c off, just remove the blower door and see if it's running. The electrical contacts may also wear out causing the motor to fail. Examined the plug at the blower motor and found it a little corroded - cleaned it and everything works fine. When your furnace isn't actually heating, though, your furnace blower shouldn't be running at all. The second problem SOUNDS like-- The Infamous Blower Motor problem. Any advice will help?. Sometimes there can be an issue with the blower motor control module which can be fixed by installing a few used auto parts instead of replacing the whole blower motor. If so I suspect that there is an earth fault on one of the wires connected to either pin 4 or 5 of the resistor. Tighten the wrench jaws so they fit snugly. Turn unit on at the on/off switch at the blower motor. You can find replacement blower motors for Mercedes-Benz S430 and learn more about them here. Never allow anyone, especially children, to operate the snow blower without proper instruction. if your blower is working but keeps cutting out then there are more chances of a faulty blower. It will come on occasionally and repeat the shutoff. The blower motor resistor controls the speed of the blower motor indirectly by relaying electrical current to the blower motor control module. These same diagnostics also aid in air conditioning blower assembly diagnosis when an A/C blower continues running. [Archive] blower not working on 5 GMC Sierra Forum. There should not be any voltage to the motor until it starts. Possible resolution: The blower motor control module seems to be the culprit for this problem based on what I've seen in several other threads and sites. The 2004-2005 has the 10-setting switch, and prior years have the 5-setting switch. In order to know which is at fault, you will have to either install a new final stage unit and see if the blower works, or test the blower before replacing any parts. So, if your furnace has not been working for quite sometime now, check the blower motor for problems. The most common symptom of a faulty blower motor resistor is a blower fan that only works on one speed, usually high. The contacts inside the relay go bad. The evaporator fan 242077705 should run anytime the compressor and condenser fan motor are running. This DIY dryer repair guide explains how to replace a dryer drive motor. This is the design of late model forced draft. If your furnace’s motor runs but the blower doesn’t move air, the belt that connects the two probably has broken. If loosening the fuel cap allows the engine to stay running it is likely clogged and will need to be replaced. If the blower fan does move freely, feel the motor to see if it is hot. Check Your Furnace Blower Fan. If you hear louder banging sounds when the blower is running, shut the system off. If so that would prove that the motor is bad. Now nothing. i've had the blower motor replaced 3 times on my 06 because it works intermittently at times. If the Start Capacitor fails the motor will most likely not turn on. If it does then you have an auger jam or or motor is weak. With the blower turned on and the a/c off, just remove the blower door and see if it's running. Discussion in 'Water Heater Forum, Tanks' started by rexles, Dec 29, the blower will run till it burns out, and it will. The car manual gives location of all fuses and what they are but not the relays. If it keeps running…replace the module. First, turn off all power to the unit and turn off the gas at the gas valve that serves the furnace. With out being able to find the make or model no of my furnace it is total elect and is not a heat pump, what could cause the blower motor to slow down. The torque to drive the motor of your electric fan comes from the magnetic field induced in the motor coils when electricity passes through the coils. On pump leaded it ran 10. If continuity is not present where indicated in the test steps above then this confirms that the blower motor resistor is bad and needs to be replaced. Typically the high - low blower cycling repeats 5-6 times over a period of 10-15 minutes then the cycling stops and the blower runs at an intermediate speed. The blower control module is the only thing I see in the circuit that would keep the fan running. Bruce Roe. We have replaced the blower motor resistor three times in the last three months and now the blower won't turn off again. Blower motor runs and slows down and then stops Blower motor runs but starts to slow down and then stops. However, if the blower continues to run at high speed with either of those tests, replace the blower motor control processor. then slow to a stop again. I believe what you are seeing is normal, unless the blower continues and never stops. So where do I find the motor? Do I have to pull out the insert to replace the motor? Is there a secret cover or something?. It also blows through the vehicle’s AC evaporator in order to provide cool air when the air conditioning system is running. 5hp) runs for a few minutes and then stops. Blower Motor Products. If I put my climate control to OFF, the blower motor keeps going. Battery was discharged two days ago. As you know, these have electric motors in them that wear out over time and will begin to make squeaking or grinding noises as the bearings begin to wear out. How To Fix Your Squeaking/Screeching GM Blower Motor. Looks like an X13 motor. Does it run on any setting (manily HI), no check the fuse, then Resistor bank, then switch then motor and wiring. This DIY dryer repair guide explains how to replace a dryer drive motor. If you are getting air flow right now. wait for the blower wheel to come to a complete stop, locate the cause and correct it. What can happen when a blower motor resistor goes bad is that the motor will run and then suddenly stop running on a regular basis. It also blows through the vehicle’s AC evaporator in order to provide cool air when the air conditioning system is running. one or more windings are acting like a brake when energised. Replaced resistor last week with Motorcraft part and that blew out two days ago. If it's normal it should run OK, and if the motor was the problem, your air conditioning freezing problem should stop. That button tells the switch whether to operate manually (run the fan all the time) or automatically (run the fan only during heating cycles). so i collected for my call and they said they were going to get estimates. Car A/C Stops Cooling or Working After a Few Minutes the idea of a relay to run 12v directly has been floated. The motor air conditioner run capacitor and the motor start capacitor. Many owners are having problems with melted electrical connectors that stop the flow of power to the blower motor. If your blower isn't working or works intermittently, don't automatically assume you have a bad blower motor. It's a pretty easy operation; the only thing you'll need is an 8mm socket with a ratchet and an extension. Jeep Cherokee 1984-2001: Why is My Blower Motor Not Working? If your blower motor is not working, learn how to identify and resolve the problem here. When the blower runs -[during heating cycle] it will continue until the t-stat is satisfied. Acura TL Blower Stopped Working: Fix. If the blower isn't running but the fan outside is, the problem could be the blower motor, it's run capacitor, or the furnace/air handler control board. Shaggy has some good points, that's happened in the past, also I would check the condition of your cabin filter, it maybe plugged and in need of replacement - might not cause the blower to stop but could slow its effectiveness. It would run, kinda low speed, for about 30 seconds and then I would hear a click and it would. It sounds like the blower is blowing full speed but the volume is super low even though it is still blowing cold. Tip: Avoid setting your fan to ON, it wastes money because it forces the fan motor to run constantly. Blower motor starts and continues running but burner will Burner runs, then stops and locks out during To help troubleshoot the GeniSys control more. I replaced the fan and limit control. If so I suspect that there is an earth fault on one of the wires connected to either pin 4 or 5 of the resistor. Air conditioner starts then stops after only a If you are saying the engine starts and runs for 15 seconds and dies and then starts again for another 15 seconds and dies. My home A/C blower motor runs for a few hours, then will not start again after reaching set temperature. I ran the diags and it said low blower RPM and I poked around on the internet and figured I needed a blower motor. Here's the issue: When the air tank is empty (no load on the motor) the air compressor runs great. The camera responds by underexposing the shot, and the snow turns grey. not drying, not blowing. If the motor spins then is the Heater and A/C Programmer, or the Climate Control Module (the one under the radio) or the data wire between the two. the silver canister under the hood near the fires wall will be all iced up. If so I suspect that there is an earth fault on one of the wires connected to either pin 4 or 5 of the resistor. The blower will then run until the firebox is cooled. It will restart if you press cancel first, it does not seem to be heating, the air coming out iis cool. It has been a couple years since this happened to me, but yes, it keeps running like the Energizer Bunny! You have to disconnect the wires to the fan control module to stop the fan. So I replaced that and it worked and we’ve run a few loads thru no problem. Blower motor problems can cause many driver complaints. This is relatively common problem of the the full sized Chevrolet, GMC and Cadillac trucks with auto a/c controls. But theirs. Here is a the blower circuit for a 2002 Dodge. It sounds like the blower is blowing full speed but the volume is super low even though it is still blowing cold. Is the motor really hot to the touch when it shuts off? permalink;. How do I test the blower motor to make sure it is defective? It has a strange three prong plug with two round prongs and one flat. Sounds like the front blower motor is starting.