Thread: Hello - Newb with Blower Motor question

Hi everyone, I am new to this Forum but not new to working on cars or other forums. Also on the Impalassforum.com with the same handle and I'm quite familair with the Mechanical and electrical side of things.

Couple of Electrical Issues....Sorry, I know it's a lengthy read but I just want to include as many details as I can up front.

1) So I have a 2004 Grand Prix with the 3.8 L engine with about 140K on her and the Blower Motor for the Heater/AC stopped working. It was doing it off and on for a bit and the last time it stopped, I hit the Dash and it worked for a bit so was assuming it was the fan motor. I found the problem, just not the fix for it yet and looking to see if anyone else has seen this.

Here's some more details on what I did...After some initial testing I've done, I have found that the Fan works fine when 12V and Ground are applied directly to it. Started testing some of the leads going into the Resistor pack and if you look at the Schematic, Ground is on Terminal A of the 5 wire plug. I have continuity from this terminal to metal/chasis ground. The 12V signal comes from a 30A fuse (Main4 Fuse 30) in the underhood fuse box and feeds directly PinC of the 5 wire plug. The fuse is good, but I have no power going to PinC of the plug....actually there was about 4.5V I was picking up with the DVM. I pulled the fuse and the 1 side of the leg has 12V so it has power.

This is where I found the problem....if I check for continuity from the leg of the fuse holder to PinC of the connector that plugs into the Resistor Pack, I have no connection. I just temporarilly Jumpered a test wire from the fuse to to a backprobe on PinC and the Fan and all speeds work. So obviusly my problem is in the wire that the Schematic shows going from Fuse 30 to PinC that plugs into the Resistor Pack is open somewhere. Has anyone else seen or have an idea of how/where exactly this single wire runs? I don't want to cut into the factory harness unless I have to but if I do I will be sure to Solder and Heat Shrink the Connections. I'm going to remove the Glove Box this weekend and see if I can physically trace the wire back and hopefully find the break.


Phew Now my 2nd issue....


For years we were dealing with a Humming and sometimes a whine that would come through the radio and would also vary with engine speed at times. A good ole RAP on the side of the dash would sometimes stop it OR make it less OR make it worse. Sometimes beeping the horn would cause it to return or hitting a bump in the road. Sometimes after turning the car off you could still hear a whine or crackling coming from the speakers that would go off after a few minutes.

I think I resolved this issue while working on the blower motor. While I had things apart, I decided to pull the dash panel and removed the Radio from the dash, cleaned the connections with electrical cleaner and reseated everything just to see if that helped. It actually seems to have stopped for now. Anyone else seen this issue or have other things I should check while I got the Dash apart?? BTW - Its the 6 disk changer with the Monsoon setup.

Many Thanks for listening and bareing with me on my long post.

Originally Posted by J57ltr

1 More than likely a bad fan motor. Brushes worn causing intermittent connection to Comm.

2 bad ground to the radio causing a ground loop. Antenna connection, ground or interference with some other device installed into the dash likely.

Thanks for your reply. I know I had a lot of info in my first post, but I did already test the motor itself and it is fine. The real problem is a break in the wire that comes from the underhood fuse panel (fuse 30) to pin C of the resistor pack in the cabin down near the blower.

Everything works fine if I run a test jumper wire between those 2 points. Just looking for the best way to find the break in the wire and ultimately repair it. Maybe my only option is to run a new piece of wire (correct gauge) in parallel to the factory harness from the fuse panel to the resistor pack connector.

Found the Problem. The schematic does not show it but this connector is right behind the Radio and has a Subharness off of it that feeds the Blower Motor and resistor pack. The Blower Motor hot Wire is the large RED Wire.



When I oulled the connector apart it was obvious that it was a little burnt. Its the 2nd pin from the left on top. I just cleaned it up as best I could, connected it back and it works fine.

Originally Posted by J57ltr

Sweet, good job. What are all of those Scotch Locks on the radio harness connected to? That check those connections especially the ground and make sure they are not touching anything. That could be the alternator whine you described earlier.

I really don't know what those are....certainly doesn't look factory to me. We bought the car about 8 years ago with about 40k on it and she has about 150 on it now. This was the first time I every had the radio out, so I know I didn't install them. I hate those kind of connectors and prefer to solder wires myself. At this point, I'm not going to mess with them since the factory radio seems to be working fine now but I will take a closer look if things act up with the radio again.

edit - check out the green wire....no insulation on about an inch of it near the connector.