2006 HHR - following symptoms:

Underhood fuse (#4) for BCM3 blows when it's hot - so no blower fan for the A/c (ambient was 95F on the drive home this evening, oh the joy). Checked with a meter - there's a dead short in the circuit somewhere (fuse pops as soon as power is applied - upped the amperage just to test - 60A blew as fast as the original).
Not sure if this is related (other than being the reason they no longer sell HHR's or Cobalts) - when it's HOT my radio works well (amplifier kicks in) - when it's <75F no amp. Also - until it got HOT the fan worked just dandy.
I've searched for info on the BCM3 to no avail - what I'm trying to figure out is the following:

What it controls (other than the fan motor) as everything else seems to work fine
Where it's located

does it seem feasible to just bypass the damn thing and wire the fan to another 12V source (the fan works fine when I provide 12V to it and it draws < 20A at startup according to my (rather nice) meter). I have no aversion to an aftermarket rheostat mounted on the dash.

Interesting - turning the fan control knob to the first position - even with the fuse blown - allows the AC compressor to be turned on ... I can feel cold air coming out of the vents if I'm going > 50MPH but that's small comfort (in a very literal sense) while sitting at a stop sign.

thanks in advance

Steve

 

Did you use the SEARCH tool? Try "blower" or "butyl patch" or "fan only runs on high".

The 2006 model year had a special, well documented, problem. There is a butyl patch on the right side under the windshield wiper, that goes bad. This allows water to get into the blower area usually shorting out the blower resistor. (it uses a series of resisters, not a rheostat)

So, what you are looking at is a 2 part repair. fix the patch and fix the resister. Both are covered in agonizing detail on this forum you only have to SEARCH.

 

I agree with donbrew you can confirm that's blower motor is blowing the fuse by unplugging the blower motor and resister and see if your short gos away

 

I'll give that a shot - what leads me to think it's something else is that it dead-shorts before I turn the fan on - but thanks -it's something to try tomorrow that I've not tried before.

 

... and throwing a 60amp fuse in to test is NOT the way to do things. You can fry wiring doing that, and start a fire. Consider yourself lucky.

 

Fire? Did someone call my name.

As whopper said: Not the way to do things.

 

True - very true - funny how if one of the industrial service techs I manage did something like that I'd be on 'em for putting equipment at risk (like a 26K ABB 120HPVFD) - sometimes I should either take my own advice or keep my mouth shut when I ignore it!

 

Ok - disconnected the resistor pack - replaced the fuse (20A) - started the car and the fuse didn't blow (nor did the fan work) - I'd prefer to check if it's the fan or the RP before I start replacing stuff - can I jumper the connector for the RP to put the fan on high?

thanks -

steve

 

If the fan was working at all it is the resister pack. I personally would not jumper it. The replacement should be available at any GM store.

I suppose you could do it. Did you bother with the SEARCH tool, somebody in there recently listed the values I think.

 

numerous times - often it seems this site is just an excuse to complain and whine about lousy GM service - meaningful answers seem few and far between. By the way, it's a resistor - not a "resister" - your spelling would suggest it had something to do with a female sibling rather than an electrical component.