A/C fuse blows when key is turned on

JERRODSKAGGS

MEMBER
2004 BUICK RENDEZVOUS
3.4L
6 CYL
FWD
AUTOMATIC
140,000 MILES

When key is turned on HVAC fuse blows. The fuse powers the AC control unit.
I have no temperature control, vent selection, rear defogger, outside/inside vent or A/C.
blower motor control works. I have replaced control unit in dash fuse still blows with controller and A/C unit unplugged.

3 Replies

HMAC300

MECHANIC
48,601 POSTS

Then you have a short in the power wire leading to HVAC or wherever else fuse powers up. It is a brown wire under dash if something has been added to dash like a switch/light etc. Then look for a screw contacting harness as it may have screwed into it.

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Thursday, June 1st, 2017 AT 6:39 AM

JERRODSKAGGS

MEMBER
2 POSTS

Okay I understand. Tell me: where would this wire come from? And how does that work? The battery cable goes to what? The "brain"? Then splits into many wires? Then goes wherever they need to? So do you recommend starting at fuse panel? I would think but?

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Thursday, June 1st, 2017 AT 2:39 PM

HMAC300

MECHANIC
48,601 POSTS

This leads from the ign3/hvac fuse then to a splice pak then to all actuators. Unplug actuators one at a time in pic and see if fuse blows if not it may just be a bad actuator. I am assuming this is a manual a/c system and not auto temp where you set temperature. If you need another answer immediately I will be available Saturday to answer this. I doubt it is from the splice or fuse panel unless it's a loose connection.

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