My 07 blower motor quit working, replaced the bcm 30 amp got high speed fan only. Then I replaced the resistor and everything worked fine, I cycled the switch several times and it worked. Then took the car out about a week later and only worked on high speed. I’m going to pull the resistor and check it out but wondering what might be causing this.

 

Maybe you have a early 2007 that needs the butyl patch under the cowl. Otherwise, maybe the connection to the resistor is loose or whatever caused a 30A overload is still extant.
Any recent electrical work?

 

No recent work, did have a wet floor this fall , replaced the butyl patch. The blower motor sounded fine when it was working on all speeds.

 

Check the HVAC control panel for burnt or melted connector

 

Checked the HVAC control and all looks great, put a drop of soder on the resistor and the fan works on all speeds but gets hot real quick the higher the speed the faster it gets hot. 2-3 seconds and it burns my fingers, turn to high or off and it cools right down??

 

It's a crude power-wasting system. The blower is slowed by lowering the voltage to it with a resistors. The resistance makes heat. At off, open circuit. No resistor, no heat. At full speed, no resistor needed, no heat.

I don't know just how hot those resitors are supposed to get, but some heat is expected. An incorrect motor with lower resistance would cause excessive heating of the resistors. So would a failing motor with low resistance due to a short in the windings.

 

guess I will order a new blower motor and give it a shot and see if the resistor still gets as hot , have a new resistor on order but don’t want to fry another one if it’s not the blower

 

High speed bypasses the resistor pack.
Sounds to me like over voltage. Like somebody tapped a hot wire in the wrong place.

 

Haven’t ordered a blower motor yet but thinking I have to , just picked up my new resistor to check things still getting hot . Pulled the blower motor and bench tested before I came in and read more info. Hooked up a battery and my tester, checked with the - jumper wire and the 10 amp tester. One way I had a 5.5 amp draw and the fan was running backwards the other way 9.6 amp draw fan was running correctly. Not sure if it means anything it seemed like the speed was the same both ways.
not sure if it’s connected but the radio seems to be acting up or more like the speakers I guess

 

As electrical motors start going bad, the motor itself starts raising the electrical resistance which COULD cause the control resistor to overheat.
I say replace the motor.
Not that difficult or expensive and chances are you will have to replace it someday.