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Rear AC stopped working ('04)

588 Views 16 Replies 6 Participants Last post by  stal023
I get absolutely nothing when I flip the switch to turn on the rear AC. Front works just fine. Where do I start troubleshooting? Is fuse 11 the fuse I check for the rear on an 04?
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Have you looked at the manual for the fuse? Starts at 5-103

There is a complete pack of wiring diagrams for our vans available online. If you have a 96 and up and have/know how to use a computer I highly recommend installing Virtualbox + the GM Techline eSI(digital factory service manual).ova Info Share - Owners/Service/Parts Manuals - Wiring Diagrams
This connection is just hanging out and I don't see where it goes. Could this be my issue?

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Can you take a wider picture so we can see where you are at in the van ...and what is in front of you?:geek:

If you are looking right at the rear AC might be one of these two spots.The lower one on the black blower cover should be black/ orange and without that plugged in the blower shouldn't work..but it appears the wire cluster continues to the upper arrow..
Looking again..your wire cluster does continue if the blower one is plugged in(lower arrow) probably where it goes..
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This connection is coming out the massive taped up wires near the bottom of the unit. There are 3 connections that I see and all have stuff plugged in.
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Check fuse 12 under the dash ("heat/ac" 20 amp) and under the hood ,driver's side #2 ("RR heat/ac" 30 amp).
Those two wires..??? They may have already been disconnected from something else.I think I would see how far they reach and see if something appears unplugged in the limited range of the two wires.

My 1990 doesn't have the rear AC..My 2004 does but I haven't had to deal with anything in that area,so really haven't looked at it.

My schematics shows an orange and black going to a box (a square on the page..called the Rear AC switch),then to the "AC resistor pack" with..(yellow/lt blue/gray ..maybe that top connection....that continues to that orange/black set for the blower motor..where that line ends.. perhaps the switch/plug in area.. is ahead of those two things(in the cluster.?I can't tell you.. ???..but that is where I would look..
Your unused plug/connector looks to be for the optional rear power outlet, which I don't think comes when you have rear A/C.
Good idea, MechBob, I forgot about that one not seeing the panel! I have the 12 volt outlet in the back of mine and the rear AC by the base of the rear driver's side door.That plug would work there and more than likely orange/black.Stal023..see if you have what looks like a cigarette lighter plug at the base of the rear door on that the plastic panel with the vent if you have it.--->

Think it might blow the rear AC fuse if it got shorted out somehow?..since the rear AC is not working..?
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No. It would not be wired into the A/C system.
Okay..same cluster..just a thought.
Okay..same cluster..just a thought.
Yes, same part of the harness, and yes that is the only other thing back there is that power outlet. Orange and black, power and ground, easy test as it's powered all the time :)
Fuses are good. Next thing to check?
Yes, that accessory outlet was common even with the rear a/c.
My 2000 parts van has one with the rear a/c.

The rear a/c units have a thermal limit fuse built into the resistor pack - similar to the rear heat units.
If it's not flowing enough air over those resistor coils, the limit fuse will blow killing power to the motor.
Check voltage at rear motor,resistor.
Before you get too deep in troubleshooting, check the rear AC switch on the dash for burned/melted wiring/switch issues... good luck.
Fuses are good. Next thing to check?
Getting voltage? Grounds good?
Before you get too deep in troubleshooting, check the rear AC switch on the dash for burned/melted wiring/switch issues... good luck.
Will do. Give me a couple of days and I will report back.
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