A/C wiring for 2006 truck PCM and harness
02-09-2011, 02:42 PM
#1
A/C wiring for 2006 truck PCM and harness I am trying to sort out my A/C wiring for my hotrod. My engine is controlled by a 2006 Silverado 2500 HD PCM and wiring harness. I have F-body accessories (including the A/C compressor) and Corvette DBW.
Question 1:
I would like to have the PCM control the A/C compressor. My car (the hotrod chassis) has a 12v A/C compressor request wire that is turned on by the climate control when it wants the compressor turned on. Unfortunately, the PCM is looking to the serial data system for the request to turn the A/C compressor. So you can see the problem... my chassis sends a 12v signal when it wants the A/C turned on, but the PCM wants the request sent through the serial data lines, which is not a simple 12v on/off switch! This is not a new problem, and has been discussed before.
I was looking through some wiring diagrams, and it looks like the 2005 Express 2500 (cargo van) has a simpler setup. Here, the van's climate control sends a 12v+ (I think) signal to the PCM, and the PCM turns the A/C compressor on. This is exactly what I want! Is there any way to transfer this part of the van's tune over to my Silverado-based PCM, so that I could have the simple single-wire A/C request?
Question 2:
Let's say there is no easy way to make the PCM control the A/C compressor. If I bypass the PCM and wire up the compressor clutch to turn on manually when requested by my car's climate control, is there a way to make the PCM turn on the fans when I turn on the A/C? I was thinking maybe if I left the A/C high-pressure switch wired to the PCM, the PCM may turn on the fans when it sees high pressure. (My harness has a 3-wire high pressure switch.)
Thanks, -Dave
Question 1:
I would like to have the PCM control the A/C compressor. My car (the hotrod chassis) has a 12v A/C compressor request wire that is turned on by the climate control when it wants the compressor turned on. Unfortunately, the PCM is looking to the serial data system for the request to turn the A/C compressor. So you can see the problem... my chassis sends a 12v signal when it wants the A/C turned on, but the PCM wants the request sent through the serial data lines, which is not a simple 12v on/off switch! This is not a new problem, and has been discussed before.
I was looking through some wiring diagrams, and it looks like the 2005 Express 2500 (cargo van) has a simpler setup. Here, the van's climate control sends a 12v+ (I think) signal to the PCM, and the PCM turns the A/C compressor on. This is exactly what I want! Is there any way to transfer this part of the van's tune over to my Silverado-based PCM, so that I could have the simple single-wire A/C request?
Question 2:
Let's say there is no easy way to make the PCM control the A/C compressor. If I bypass the PCM and wire up the compressor clutch to turn on manually when requested by my car's climate control, is there a way to make the PCM turn on the fans when I turn on the A/C? I was thinking maybe if I left the A/C high-pressure switch wired to the PCM, the PCM may turn on the fans when it sees high pressure. (My harness has a 3-wire high pressure switch.)
Thanks, -Dave
02-09-2011, 11:49 PM
#2
To answer your first question as well as I can, From talking to HPTuners there is no way to do that swap. It has been requested as a feature but they have not responded. I`m wondering if it is possible with EFILive 7 though since it sounds like a segment swap (or maybe it would be a partial segment swap) to me.
I haven`t figured out how to use the pcm to trigger the fans if it does not control the AC. I am going to have to figure something out though, as my brothers swap has the serial data request signal and he said he does not want to go without A/C again this year.
