2004 Suburban 1500 5.3L 4x4 Keeps Blowing AC Fuse

[Brewtal66]

Hey everyone,

 

As the title states, I have a 2004 Suburban, 1500 with the 5.3L and it's a 4x4. The AC keeps blowing the 10A fuse. 

 

Backstory:

A few weeks back the family and I were driving a few hours away in the car. I stopped halfway(but didn't turn off the car) to fill up with gas and grab snacks. When I came back in I noticed the AC wasn't cold, but all the blowers were going and the light was on the dash. I popped the hood and noticed the compressor wasn't going, so I checked the fuses and found that 10amp AC fuse was blown. I replaced it with a 15 amp(only one I had) and finished the drive down. For the rest of the day it kept blowing the fuse, and I eventually worked up to a 30amp fuse in order to make it home. I know that's bad but it was hot and I have a newborn so no AC for 2 hours wasn't really an option. 

 

At home, I found this thread(that's pasted below). Seems like the exact same problem, so I went ahead and replaced the AC clutch earlier this week. Mind you everything appears to be working 100% normal. When I pop a new fuse in, the AC pump works and the AC is ice cold. After replacing the AC clutch, it's blowing the fuses again. 

I'm not really sure where to look or where to start for fixing this issue. It just randomly started happening. Maybe it's a wire that's shorting out? The only semi-consistent thing I notice is that if the car is running, and I put in a new fuse, it won't blow unless I drive it AND put it back in park. Driving for hours its fine. Only once I put it in park it seems to blow then. 

At my wits end. Any ideas? The only thing I can think is the wiring to the clutch compressor is shorting out somewhere intermittently. Thank you for any suggestions!!

 

[Jsdirt]

No A/C may be inconvenient, but a FIRE is SUPER inconvenient ...

 

You've got a shorted wire, or a really bad connection in the fuse box that's heating up the fuse and melting it.

 

Fuses blow for a reason - usually excessive current draw, probably due to a short. Your choices are, either start digging and looking in areas of heat and vibration for the chaffed wire, or, cut the old wire and run a new wire from the control unit to the compressor. Neither job is much fun, but these are the only choices. A simple 1 minute continuity to ground check could have saved you the cost and effort of installing a new clutch. That's why I always tell everyone, "TEST - don't guess!"

[Brewtal66]

On 8/29/2019 at 9:37 PM, Jsdirt said:

No A/C may be inconvenient, but a FIRE is SUPER inconvenient ...

 

You've got a shorted wire, or a really bad connection in the fuse box that's heating up the fuse and melting it.

 

Fuses blow for a reason - usually excessive current draw, probably due to a short. Your choices are, either start digging and looking in areas of heat and vibration for the chaffed wire, or, cut the old wire and run a new wire from the control unit to the compressor. Neither job is much fun, but these are the only choices. A simple 1 minute continuity to ground check could have saved you the cost and effort of installing a new clutch. That's why I always tell everyone, "TEST - don't guess!"

I get the fire is super inconvenient. BTW, nice 71/72 Elky in your profile picture. I have a few '66 Chevelles myself. 

 

I did swap relays with another one and that did nothing as well. Relay is getting warm when it's running as well. 

 

I tried to dig into this a bit this weekend. I looked at the wiring from the compressor back to the starter area and didn't see anything major, although I know that doesn't mean it couldn't be screwed up inside. I couldn't see where it goes from the starter area though - does it go up the backside of the block? I did take an OHMS meter and hooked it the the two wires that feed into the compressor and it's not showing anything there. 

 

I'm okay with running a new wire. I'm going to try to find a wiring diagram now to see where it all runs. 

[Jsdirt]

Thanks. I sold that one 8 years ago like an idiot, and bough the '07 Silverado. I should have kept it! Never gave me any grief aside from minor stuff like hose clamps loosening with time (11 years) and such, but the Silverado has been one big headache the second it left the showroom. Never again ...

 

Anyway, sounds like since the relay is getting warm, you have control of the relay, meaning, the head unit is turning on the relay. So that  should mean that all you need is power from the relay, and ground from the coil. I think you have that, since it blows the fuse. Even though your coil is new, I'd still check to make sure it's not internally shorted. A simple ohm check of each wire to ground should suffice. Of course, one wire should be direct to ground and have no, or very low resistance. The other should be much higher. If both are the same, the coil winding is shorted. Wouldn't shock me to see a bad one right out of the box these days.

 

If that checks out, I'd run a new wire directly from the supply (or secondary) side of the relay to the coil, and eliminate the hassle of trying to hunt down the short. You'll probably have to pull the under hood fuse box to do so, which can be a PITA, but everything will work the way it should. The other option is to control the coil with a switch, so long as the power to the coil passes through the low pressure cutoff switch first, so the clutch cycles on its own.