Retro Fitting Ac

dmjr77 · March 7, 2009

I am looking at a 1997 GMC 3500 1 ton Dump truck that has no AC in it. Is it possible to retrofit to get ac in it?

Thank You

bill190 · March 8, 2009

I don't know about your specific vehicle, but I am going to do this with a car I have. I found the same model car at a wrecking yard with factory air.

So what I need to do is transfer all the mechanical stuff, then look at the factory wiring diagram and find all the associated electrical items (relays, switches, etc.) and transfer those as well. And I will be looking to see if my car has the wiring harness(s) for factory A/C. Also my car may have the basic wiring there, but might need an additional wiring harness transferred? Just need to compare both vehicles.

It is possible that a larger engine might have been installed for a vehicle with A/C as opposed to one without, but I checked on that and this car had all the same engines.

The one question I have which might not be easy to answer is if there was different programming for the engine computer for one with A/C as opposed to on without A/C? I'll need to read all I can in the factory manual on how these things work, but this might be a show stopper!

Other than factory, I know there are businesses which install add-on A/C. Might want to try the dealer and see if it is possible for them to install factory A/C or not. Never hurts to ask!

qaz5eng · March 9, 2009

I performed the swap on my 1996 6.5L 2500HD, the wiring with connectors should be there rubber banded or taped off on the engine end. The HVAC controls and airbox will have to be swap out for one that has electric controls for the AC. The firewall will need to have a hole drilled for the top AC line. I bought mostly new GM parts for the install except for the cabin controls & airbox which came from an wrecked 1998 and a NOS AC compressor off of craigslist. I took my time and got it done in 8 hours. The most time consuming part for me was was dropping the dash and steering column. If you are doing a swap with parts from another truck make sure you keep everything clean and sealed(all ends covered) so no dirt enters the AC system.

Cheers,

Tom

bill190 · March 10, 2009

I pulled the A/C parts for my car A/C project today. As it turned out, there was a wiring harness which was not on my car. And looking at the factory wiring diagram (for my car), the A/C compressor is actually switched on by the engine computer! And the A/C switch sends a signal to the engine computer. Then a bunch of relays and electrical connections.

Anyway I don't know about your truck, but be sure to closely compare all the wiring in your truck with one in a wrecking yard to be sure you get all the associated wires, relays, etc. (And look at the factory wiring diagram for the A/C to find the locations for all this electrical stuff.) There could be one little relay mounted somewhere where you would not think to look. Also there could be a fuse or two which is not installed.