2000 Oldsmobile Bravada AC FUZE BLOWING

REPTECH

MEMBER
2000 OLDSMOBILE BRAVADA
6 CYL
AWD
AUTOMATIC
110,000 MILES

- 10A AC fuze in engine compartment fuze box is blowing when engine is running and AC is selected.

Trouble shooting to date:
- Replaced fuse and removed compressor connector, fuse still blows.
- Replaced fuse and removed cannister pressure switch. Fuse did not blow.
- Jumped cannister switch connector and powered up. Blew fuse. This eliminated the cannister switch being bad.
- Tried to manipulate the control face temp switch but fuse still blows.

Note: AC blew fuse 2 times before this and I was able to replace fuse and move out. Blew the second one after about 500 miles with some extended driving. Same thing happened the 3rd time. Now, as stated, blows fuze right away. Engine must be running and AC selected for fuse to blow--with or without the AC compressor being connected.

5 Replies

WRENCHTECH

MECHANIC
20,761 POSTS

How do you figure that. You just jumped power to ground which is a direct short circuit. That would blow any fuse.
That's a real good way to fry the quad drivers ion your computer too.

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Monday, August 23rd, 2010 AT 8:10 AM

REPTECH

MEMBER
3 POSTS

Let me clarify my error. I am talking about jumping the wires in the connector that attaches to the connector in the round thing-a-ma bob that sweats (gets cool and wet) when the ac is working properly.

Better description. Jumped the wires in the connector that attaches to the low pressure switch in the accumulator. I have always used this approach to ensure the compressor works when having ac cooling problems. Granted, this doesn't say the compressor actually works, but it does let you know that the clutch kicks in on the compressor. On other occassions, I have found 2 bad switches in the actuator this way and yet to blow a fuse. In this situation, as stated, fuse is blowing when AC is selected and engine is started. Logic would have one believe that the short is in the compressor. However, if I disconnect the compressor, start the engine, and select AC, fuse still blows. The control face is the auto climate control type with rear window de-ice. Everything else seems to work.

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Monday, August 23rd, 2010 AT 2:05 PM

WRENCHTECH

MECHANIC
20,761 POSTS

Your description of a canister switch sounded more like a canister solenoid which would have been powered.

That cycling switch can't have anything to do with the short. All it does is signal ground to the PCM and has no power.

The 10amp fuse marked A/C passes through the relay and then to the compressor so the compressor, the connecting wiring or the relay are the only things that can burn it out. When you unplugged the switch, you just de-energized the relay so It really looks like the problem is either the compressor or the wire leading to it.

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Monday, August 23rd, 2010 AT 2:56 PM

REPTECH

MEMBER
3 POSTS

Thanks. Can't tell what is going on. I replaced the relay and fuse yesterday afternoon and it began working fine. This morning I drove to work and all worked fine, to include cycling the system. Went to get gas at lunch and GTG. Cranked up after filling and pop, no air compressor. Checked at home and 10A fuse was blown. Replaced and it blew again. I too suspect the compressor, but again, I check the system with the compressor unplugged and when I started the car with AC selected, fuse blew. However, this was after the relay could have shorted as a result of a bad compressor. Is there any way I can run a system or wiring diagnosis? Maybe confirm the compressor bad using an inline breaker/fuse wire hooked straight to a 12 volt source?

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Tuesday, August 24th, 2010 AT 3:08 PM

WRENCHTECH

MECHANIC
20,761 POSTS

I have already looked ad the diagram and the only things between the fuse and the compressor is the relay and some wire. Since it didn't blow with the switch unplugged, that means everything is OK up to the relay and including the relay when it's not energized. The problem has to be between the relay and the compressor and that is just a direct wire that could be pinched or melted somewhere if everything you have told me is true.