[Sharp07GT]

My blower motor on the heat/ac/defrost works sometimes, sometimes it stops and if I hit a rough patch in the road it starts working again. I can wiggle the wiring harness that sits just behind and below the battery and it will come on momentarily. I think it's in the wiring harness ,but I have no way of isolating it. Any help would be greatly appreciated .

 

[12ltz]

replied in another thread but copied answer here also

Might want to check to see if battery acid ate thru some wires, when you wiggle the wires they conduct and the blower motor works seems to point to that area. Might need to remove battery and tray to check wiring in that area.

Good Luck

 

[Sharp07GT]

Thanks, ill check that.

 

[jrd0304]

I'm having a similar problem. After trying a new switch, resistor/control module, and blower motor, I have it narrowed down to something messed up in the dash wiring. There is a harness that runs from the fan / vent switches and snakes somewhere down through to the 5-wire blower control module/blower motor. I smacked the dash between the ashtray and switch panel yesterday and it kicked back on after cutting out on me for a few minutes. I was not able to get to the wiring harness from the front of the dash. I am thinking I may have to go in from underneath somehow. The way I found out it was a wiring issue in the dash after attempted component replacement was that when it quit on me, I had the dash off and the switch panel sitting there unbolted turned to on, and I reached back into where the switch panel connects to a harness under the radio, wiggled the wires, and it kicked back on. It's still cutting out on me intermittently, so I'm not sure what the next step is. I can't track down a part number for the harnesses, some people have run a bypass to the hot red wire down going into the blower control module itself, but I'm not sure how they're splicing that in exactly, and I'm a little hesitant to do that in fear of shorting out something else.

 

[jrd0304]

I've been searching around the web for a possible cause - I'm not there yet - there are a couple misc. threads indicating a possible bad ignition switch - I highly doubt it, any thoughts? Also found something VERY interesting here:

http://pdfrepairmanual.com/search/2004+impala+intermittent+operation+of+blower+motor

The 04-05 Grand Prix has the SAME Blower Control Module has my 2004 Impala and probably other 7th gen years as well. I might try this and see what happens. If I do, I'll get you guys know.

 

[jrd0304]

One thing I did as a workaround to get me by since it's cold. Disconnect the battery. Get a heavy duty 12V accessory plug for the cig lighter and some extra wire. I recommend a heavy duty one since a cheap one might get hot or melt. Take the black kick panel off from underneath the glovebox. Unplug the connector at the blower motor. It should have a purple and black wire. Cut and splice the hot from the accessory plug into the purple wire. Cut and splice the ground from the accessory plug into the black wire. You should now have everything taped up so you could use the switch if you want, but the accessory cig plug as an optional backup. Reconnect the battery. Now, all you have to do is turn the fan switch off, and plug the accessory into the cig lighter for the blower to kick on. You'll only get one speed, but you won't get stranded because your defogger or heat isn't working. This will at least get you by until you can find the cause of the problem. Of course, make sure it's unplugged when you turn the car off since it's constant hot and will drain your battery. Until I can find the problem this has been bailing me out.

 

[jrd0304]

Found this as well concerning the ignition switch.
Blower motor issue - Chevrolet Forum - Chevy Enthusiasts Forums

I might try this as well. Argh.

 

[jrd0304]

Put the new ignition switch in, did not fix the problem.

 

[jrd0304]

For me, it was an issue with the harness above the ashtray. See post:
http://www.impalaforums.com/chevy-impala-7th-gen-discussion/335678-2004-blower-motor-issues.html

 

[Big B]

One thing I did as a workaround to get me by since it's cold. Disconnect the battery. Get a heavy duty 12V accessory plug for the cig lighter and some extra wire. I recommend a heavy duty one since a cheap one might get hot or melt. Take the black kick panel off from underneath the glovebox. Unplug the connector at the blower motor. It should have a purple and black wire. Cut and splice the hot from the accessory plug into the purple wire. Cut and splice the ground from the accessory plug into the black wire. You should now have everything taped up so you could use the switch if you want, but the accessory cig plug as an optional backup. Reconnect the battery. Now, all you have to do is turn the fan switch off, and plug the accessory into the cig lighter for the blower to kick on. You'll only get one speed, but you won't get stranded because your defogger or heat isn't working. This will at least get you by until you can find the cause of the problem. Of course, make sure it's unplugged when you turn the car off since it's constant hot and will drain your battery. Until I can find the problem this has been bailing me out.

Do you remember where you got it and which part? I'm running into this issue and I'm not looking long on cash or the thought of messing around with this crap when it's freezing cold.

Otherwise, this is exactly what I want to do right now.