A/C compressor blowing its fuse

[crazyd]

The 15-amp fuse in the passenger-side underhood electrical center keeps blowing when I turn on the A/C.  This has gotten progressively worse as it only seemed to blow last summer under hard acceleration.  Thinking it was a bad clutch I replaced the compressor, but the problem persists.  I tried fuses up to 30A and every single one blows as soon as I hit the A/C.  Suggestions?

[digitaloutsider]

I'd check for wiring being chafed somewhere. It sounds like it's shorting. 

[mfewtrail]

Did you replace the coil with the clutch or just the clutch?  Blowing a fuse immediately is indicative of a short as digitaloutsider suggested above. I'm assuming you have a chafed wire somewhere just from your previous symptoms in your older thread about blowing the ac fuse when accelerating at WOT or after WOT acceleration.  WOT equals more engine movement, so more potential for the chafed harness to move and contact ground. Never substitute larger fuses. That's a good way to smoke wiring or even potentially start a fire.

 

 

[crazyd]

So the point of using a larger fuse was only to determine whether there was increased load from a bad clutch or increased resistance, not to leave it there permanently.

Turned out the green wire was chafed against the motor mount about 8" downstream of the compressor plug because of deteriorated loom that was pretty much all gone.  Good call guys, thanks!  I haven't been happy about the routing of those wires around there since the last time I took the engine out, it seems a bit more snug than it should be, so now I'm definitely going to have to do something about it.

Anyway, it's running and charging back up now on can #2 and blowing cold already.  Just in time for fall!

Thanks guys!  I even found a vacuum leak on my MAP sensor that would explain some drivability issues.

Edited August 20, 2020 by crazyd

[Cutlass350]

3 hours ago, crazyd said:

Turned out the green wire was chafed against the motor mount about 8" downstream of the compressor plug because of deteriorated loom that was pretty much all gone.

Deteriorated looms are Very Common in GM cars and W-bodies.  GM uses loom material that lasts ~10 years.  Like the rest of the car, the loom is like many components of the car that are "cost optimized" to produce a (hopefully) acceptable mid-expectation on life-span.

Imho, in fact, GM lead that design philosophy far before just about every vehicle manufacture started doing the same exact thing.

 

The difference is how long each manufacture sets a target life for different components.  In general, longer life for a component means more cost.  More cost means less profit.
Less profit, and a company can become like Mercedes Benz and BMW and barely survive, then end up producing pure cr*p that makes GM's biggest steaming piles of cr*p vehicles look like shinny gold.

That's life in the real world competing against competition.  It's far from easy. 
Toyota has been able to survive, and thrive, by producing quality vehicles, with long expected life-spans, for not more, and get/convince people that the slight extra cost is worth it.  Yea, it sounds easy to do, but it's not.  And, Toyota has had screw ups (some trannys/cats/etc).  So, there's no guarantee that a specific Toyota model/year will be worth that extra cost.

Fwiw, most vehicle manufactures really care about the people that buy a new vehicle every x-years.
Those are the people the vehicle manufactures make money from.  Not the people that keep cars for a long time, or buy used cars. 

Yes, long explanation.
The point is to replace all of the wire looms you can.  And also realize that you have to be careful about maintenance, preventive maintenance, and checking things on older vehicles.

Btw, for any wire loom, brake line, etc  that goes near an exhaust area/part, I suggest thermal wrap around the item.
Brake lines rusting from the heat of the down-pipe are also common for GMs.

Good Luck!
 

 

 

 

Edited August 20, 2020 by Cutlass350

[Psych0matt]

Manufacturer

Sorry, drove me nuts reading that