Blowing Air Conditioning Fuses

**ls1camino** · 07-25-2011, 04:42 AM

This is on my brother's 2000 Grand Am 3.4L.

When he bought the car, the AC worked fine, two weeks ago it went out for no reason. I thought it was a fuse, and I replaced 3 different HVAC fuses (one on the passenger side interior and 2 under the hood). Nothing changed, so I figured it was the blower motor. While pulling appart the interior to replace the blower motor, I noticed ANOTHER fuse panel, this time on the passenger side interior. I pulled the cover off and found another HVAC fuse (20A). I pulled it and found it was blown

So, I replaced it with another 20A, and as soon as my brother turned the ignition to ON (didn't start the car) the replacement fuse blew. I didn't have another 20A, so I replaced it with a 30A. Turned that ignition to ON and that one popped too. I'm lost as to why this is happening. Stock is 20A, but it's not even lasting a second upon startup.

What should I check next?

**Knight** · 07-25-2011, 07:37 AM

Sounds like a short. I'd see if you could trace the wiring from the fuse to wherever it goes. Might be a wire that is shorting against the chassis or something.

***SMWS6TA*** · 07-25-2011, 01:29 PM

did you jump start the vehicle recently? Sometimes the surge can fry the wire harness if the cables are not grounded.

Looking for electrical shorts is a nightmare. Good luck.

**cammed goat** · 07-25-2011, 02:37 PM

Originally Posted by Knight

Sounds like a short. I'd see if you could trace the wiring from the fuse to wherever it goes. Might be a wire that is shorting against the chassis or something.

^^This.

**Cutlass** · 07-25-2011, 05:48 PM

Check the blower motor resistor. Super common failure point on that car. Usually just causes the low blower speeds to not work, but could be shorted and blowing the fuse. Next most likely thing is the blower motor itself.

Here's a video how to for blower resistor replacement. Its a little bit of a pain in the butt.