Hey everyone, I'm hoping to gain some insight on my situation here.

I have an 06 Monte with V6 3.5L

I'm having problems with my AC. It stopped working recently and I've been trying to properly diagnose the issue so that I can better remedy the problem.

The 10 amp fuse in the underhood fuse block keeps popping when I run my AC. When the compressor and clutch is running, the air is nice and cold as it should be. It doesn't pop right away when idling, in fact it will sit and blow cold with no issues. However, as soon as I start driving, the 10 amp fuse pops about 3 to 5 minutes into me driving. This is driving me crazy.

The clutch on the compressor engages properly when the fuse is still good. The air blows cold when the fuse is still good. The air coming out of the vents is good and strong so I really don't think it could have anything to do with my blower motor.

I've checked the pressure (only from the low side) while running and it sticks around 30 to 40 psi when idling. I have no way of monitoring the pressure while driving when the fuse pops.

I don't have a lot of money to throw at this but I really need my AC since I am in southeast Texas and it gets sweltering hot here. Anyone have any ideas here? I want to have a better idea of what I'm facing here before I start putting money into this and hiring mechanics.

 

Am I in the wrong forum?

 

This is the right spot for a question like this. The downside is this forum is fairly small and this is a very specific / uncommon issue.

I've never heard of anything like that before, but I'd look at the circuit diagram to see what all is on that circuit. Then I'd take the multimeter out and measure actual amperage draw including revving the engine in park to see how it behaves.


I'd follow the wiring through for that branch to make sure the wiring isn't damaged anywhere (perhaps causing it to short to ground at a pinch point somewhere) and I'd wiggle the plug (if you safely can get to it) to see if its shorting when moving) and that you've got good clean connections throughout.

If the clutch is the only thing on that circuit and the wiring is all good- the clutch itself just draws too many amps some times, then replacement is the only logical step at that point.

 

Oh man, thanks for replying. I appreciate the info here, lots of good places to start looking. I don't have a multimeter yet but I plan to get one soon. I can't safely reach the plug on the compressor while it's running.

I have noticed that after 20 or 30 minutes of idling the 10 amp fuse will pop. But as soon as I start driving, even after immediately changing the fuse to a fresh one, it pops less than 3 minutes in.

I'm having the damndest time with it. Being in southeast Texas isn't helping, either. Not to mention that I was a victim of a hit-and-run about 2 months ago. I was rear-ended in Houston traffic and they disappeared into the traffic. My muffler was bent so now it runs a lot louder than before, more than I certainly care for. Especially when driving 65 with the windows down, you can't hear yourself think. My poor kid hates leaving the apartment now, poor thing. I can't blame her, though.

I can't afford a replacement on the clutch or the compressor entirely, so I'm really hoping it's something I can manage like a grounded wire or etc. Here's to hoping!

 

I think picking up a multimeter is a good starting point. There are plenty of fairly cheap functional options out there these days. The stuff you need to measure for basic troubleshooting (DC voltage, resistance, amperage) is available on just about every unit. TBH they're indispensable for doing electrical troubleshooting.

While you're waiting for that to arrive, I'd be looking through the wiring from fuse to clutch to see if anything looks damaged or if any of the plugs are corroded/ damaged. Id also unplug the compressor while the cars off to at least look at the connector and make sure its in good shape / is making good contact.

Once you get the multimeter then you can jump into measuring what's going on.

 

Pull the connector off the AC compressor. Take a multimeter and connect the leads to the tabs inside the socket. Set the meter to ohms. It should read 2 to 5 ohms. I suspect the AC clutch magnet has gone bad or is in the process of going bad. You can do this fix yourself $50 to $75.

 

This is a failure condition I've never heard of but I'm not an A/C mechanic.
I think magnet failure (failing) makes sense but I don't know enough about our systems to understand what causes it to draw more power and blow the fuse under load? Does the BCM monitor a pressure sensor and try to account for a slipping clutch? Does that clutch require a special puller tool to remove (and reinstall) it? Could the compressor be failing and create the same high power draw?

 

When the AC is activated, the second electric fan comes on for additional cooling. This, combined bad a bad AC clutch coil, can cause enough current draw to pop the fuse.