Ac swap question

[chev-obsession]

Hey guys,

I’m in the middle of my ls swap, and looking forward at what I have ahead of me. I need to find a way to make the factory AC controls turn on the ls A/C compressor. I was looking at my factory AC wiring harness and it looks like when the diverter flap opens, it pushes on a switch that has 2 wires (yellow and green) looks like the green would go to the SBC AC compressor. The company that I had tune and rework the LS harness and pcm gave me an “AC request” wire going into the pcm.

Can I run the green wire that originally turned on the SBC ac compressor to the “ac request” wire going into the pcm to tell the pcm to turn on the ac compressor? Hope that makes sense! Any help is appreciated.

[ls1nova71]

Yes, that would be how its wired. However, it will need a relay, does your harness have that? Also, it generally only works on older engines. What year engine/PCM are you working with?

[chev-obsession]

Originally Posted by ls1nova71

Yes, that would be how its wired. However, it will need a relay, does your harness have that? Also, it generally only works on older engines. What year engine/PCM are you working with?

Yes, the harness has a relay for the AC system. As far as the year... It's an '05 from a tahoe, its the blue/green PCM. The company who did the work said they made the PCM think it is an express van since they are behind the times from the trucks/suv's and that it should work the ac system through the PCM.