Blower Motor Probs

[kamikaze_k77]

Working on a friends car - 2005 Chevy Impala with the 3.4L motor. Friend said the blower motor stayed on after shutting the car off and removing the keys. He brought it over tonight and this is where things are at... The blower motor is toast (locked up and VERY black inside the windings) The 30 amp fuse in the fust block under the hood is blown. When the fuse is replaced, I have a solid 12.3 volts at the blower motor connection. What I cannot seem to do is get the voltage to reduce when adjusting the fan control. Still have a solid 12.3 volts at the blower connection when the car is off and keys removed (and door open). There is a small module behind the blower motor with some aluminum fins going into the air ducting that I pulled out and as far as i can tell is the resistor for the blower motor. I have no schematics for this car. Anyone have an idea why my volatage is locked at 12.3 at the blower?? Any help would be appreciated!!

[j cAT]

with this vehicle I can't say for sure but usually the resistor assy is also the relay control as well check it out at the auto part store...if the blower shorted out ? 2005 ? OK ,,,this would cause the relay contacts to weld together..are you sure the blower takes 30 A?

[kamikaze_k77]

I'll put it this way (since it's not my car). I know my friend has not replaced the fuse and there was a 30A in there when I got to it.. Thats all I know (as i said, I have NO drawings or info on the electrical) I have nto worked on this new of a heater, and so I'm not sure what exactly the module behind the motor was. It has a set of aluminum fins going into the air ducting. It has a 5 wire harness labeled as follows: M+ and M- (lead going to the motor) GND, BAT and SIG. Fairly strait forward. I ASSUME this is the resistor pack for the blower control. (correct me if i'm wrong) What I'm wondering is if there is 12V constantly being supplied to the motor, is the relay module possibly shorted? OR, is it possible that the signal going INTO the relay pack is somehow sending a constant "full on" signal? My friend doesn't have a ton of money to throw into this, and I don't want to buy a $100 module that I cant' return. Is there some way I can test this out??

[j cAT]

Originally Posted by kamikaze_k77

I'll put it this way (since it's not my car). I know my friend has not replaced the fuse and there was a 30A in there when I got to it.. Thats all I know (as i said, I have NO drawings or info on the electrical) I have nto worked on this new of a heater, and so I'm not sure what exactly the module behind the motor was. It has a set of aluminum fins going into the air ducting. It has a 5 wire harness labeled as follows: M+ and M- (lead going to the motor) GND, BAT and SIG. Fairly strait forward. I ASSUME this is the resistor pack for the blower control. (correct me if i'm wrong) What I'm wondering is if there is 12V constantly being supplied to the motor, is the relay module possibly shorted? OR, is it possible that the signal going INTO the relay pack is somehow sending a constant "full on" signal? My friend doesn't have a ton of money to throw into this, and I don't want to buy a $100 module that I cant' return. Is there some way I can test this out??

the resistor module usualy has a relay..if the relay controling contacts are shorted together this would cause your problem..

the use of a 30A fuse to me is too high BUT I don't have the circuit diagram to conferm this..I would say 25A is the highest used from what I've seen in other vehicles..

the resistor blower motor control module should not be 100.oo..maybe at the dealership it is..also if the blower motor is cooked you will need a new one which on a 2005 model seems too early to fail..

the use of a scrap yard is a good option to try out various parts and confirm what the circuit uses for fuse size..

normaly owners will install larger fuses when the fuse continues to blow, in the hopes of resolving this issue , only to have the failure spread to other componets..

the module that the blower connects to is the correct part to get..with a new motor and making sure you have the correct sized fuse this should be it...look at the fuse box cover for fuse sizes and the locations..did this person own this new or is this a used vehicle?

reply back with whatever you found..