A/C keeps blowing fuse

Tiny
WAYNE WILDA SR.
  • MEMBER
  • 2008 CHEVROLET UPLANDER
  • 3.9L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 140,000 MILES
I just put a new a/c unit in my Uplander and changed the serpntine belt and now the a/c keeps blowing the fuse after about ten or fifteen minutes. I have checked the diode and it is still good and took the plug off compressor and had car running for twenty minutes and fuse dosent blow so I am at a loss as to what the problem is.
Saturday, September 21st, 2019 AT 3:31 PM

3 Replies

Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

Any time you have a fuse that blows that means that there is a short to ground in the circuit(s) that the fuse is protecting. This happens because of Ohm's Law, the laws that govern electricity in your automobile. Ohm's law states that if one of the three properties of electricity is constant, which one always is in a vehicle(Voltage-Battery Voltage) and one of the other two goes down(Resistance-Resistance drops to zero with a direct ground path back to the battery) then the last property(Amperage/Current-Amps will go to the battery amperage rating) must go up proportionally. The amps will quickly exceed the Amp rating of the fuse and POP, the fuse blows just like it was designed to and protects the circuit for being welded together or an electrical fire. In the diagrams down below I have included the wiring diagram for the AC circuit in your vehicle as well as a guide for how to find a short to ground in an automotive electrical circuit. Please go through these guides, check your vehicle's AC circuit, find and repair the short to ground, and report back with how everything turns out, please.

Thanks,
Alex
2CarPros
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Saturday, September 21st, 2019 AT 4:01 PM
Tiny
WAYNE WILDA SR.
  • MEMBER
  • 2 POSTS
Well we found out that the wiring is not at fault the new compressor is drawing too much power and blowing the fuse. We wired around the wiring harness and went to a hot and a ground and the compressor only runs a few minutes and blows the fuse. The compressors internal winding is at fault not the wiring.
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Friday, September 27th, 2019 AT 10:24 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.
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Sunday, September 29th, 2019 AT 12:55 PM

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