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Discussion Starter #1
The blower motor on my 2004 slt was acting weird for awhile--sometimes the blower speed was low or sometimes the blower motor would not come on at all. The blower motor was recently replaced with the compressor but the problem continued. I discovered that I could put pressure on the connector harness that goes to the blower speed resistor and the blower motor would come on. I took it back to my mechanic a couple of months ago and they found that the harness had melted and that was causing the blower motor to act up. Today I was in the front passenger seat and I could smell burning and when I touched the connector it was very hot. Any ideas as to what is causing this?
 

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What causing it is high current draw due to high resistance. Either the motor is defective, or the resistor assembly is defective, or the wiring contacts are not seating properly, are loose, or corroded. What happens very typically is a failing motor will draw increasing current, causing the resistor to overheat, which will damage the harness plugs and create a situation where you end up replacing everything.
 

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Discussion Starter #3
The blower motor, harness and resistor are all new. The blower motor was replaced in April, and the other two parts in June.
 

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You could still have a loose connection, but bear in mind that these connections normally will get quite warm under a full load.
 

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Greetings. It does sound like your blower motor is bad. Whether it's new or not it could still be bad. It does happen. Also as mentioned check the connector for burning or melting. With you description, I'm going with the blower motor. Let us know what you come up with.
 

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Discussion Starter #6
I just got my Durango back from the mechanic and he said it was a bad blower motor. We'll see how long this one last!
 

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Time will maybe tell. The connector should not get hot under full load which is full speed as the resistor is not used at full speed only for the lower speeds. High current load is when you have low resistance. Think about it no resistance is a dead short. One needs to be sure there isn't anything keeping the airflow over the resistor as that is what protects it. Make sure there is an air restriction that is overloading the motor. Like one of the doors stuck or partially stuck. Many vehicles are known for broken air doors, all brands. It started when the makers went to stepper motors to actuate doors and the stops would break off as the computer would cycle the door every 20 starts of the vehicle. Once the stops broke then the door becomes the stop and it breaks also leading to various problems.
 

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Time will maybe tell. The connector should not get hot under full load which is full speed as the resistor is not used at full speed only for the lower speeds. High current load is when you have low resistance. Think about it no resistance is a dead short. One needs to be sure there isn't anything keeping the airflow over the resistor as that is what protects it. Make sure there is an air restriction that is overloading the motor. Like one of the doors stuck or partially stuck. Many vehicles are known for broken air doors, all brands. It started when the makers went to stepper motors to actuate doors and the stops would break off as the computer would cycle the door every 20 starts of the vehicle. Once the stops broke then the door becomes the stop and it breaks also leading to various problems.
You're completely wrong. Increasing resistance will increase current draw, and increased resistance will increasingly radiate energy as heat, up to the point of thermal failure. Any electrical circuit contains resistance, as a fundamental property of the conductors used. Any wire or connector subject to a current load that is an appreciable proportion of it's ultimate rating will build up some heat, often because the connector elements represent a both a higher resistance point in the circuit, and because their effective cross section of contact (especially if they are worn or loose) may be less than the wire itself. This is not abnormal. Hook up a high current draw device like a heater blower to a thin little wire, it will get red hot and fail...due to resistance. This is electronics 101, which I suspect you never took.
 
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