Air conditioner signal integration

[LS1GMCTruck]

Nope, was running a Sanden compressor so I just triggered it from the 93 signal wire to the clutch and it stayed on all the time, no cycling. The coils would freeze up from time to time and I'd have to turn the a/c off so the fan could thaw it out.

Red, don't you mean, you just had it triggered from the accumalator pressure switch wire, via the A/C request relay?

[RedHeartbeat]

I don't have that switch anymore. I had a trinary switch installed in the high pressure side. The green wire that used to go to the accumulator switch now goes to the trinary switch and then to the clutch.

[kewljay223]

i know this is an old thread but im in the same boat right now. ive got the fans wired for low/high and pcm is tuned for it and im ready to get the lines fabbed up for the compressor but if there is no way to controll the fans/idle using a regular 12v signal instead of the class 2, then i might as well scrap this plan and just do something else... which will be uneccesarily expensive!!!

i know i can get the fans to kick on high bypassing the computer with a few wires and a diode if i have to. but im concerned about the idle. how bad is it when the compressor is engaged? does it want to stall out? has a solution been figured out yet?

[chevy_addicted]

Sub'd

[capricefrk013]

I looking for this fix to help out in any way I can for those looking for it.

I found a post on ls1tech about it. Seems like it can be fixed in a tune. As mentioned above, HPTuners doesnt have anything yet.

http://ls1tech.com/forums/pcm-diagno...ntrol-pcm.html

Stock PCM has full control over the A/C compressor.
To enable a standar 12V signal for the A/C request (instead of class 2) you need to change it with Tunercats or Jet DST. HPTuners currently doesn't have access to change it.
There are more parameters to be modified, but id works good. I have installed a few swaps with A/C and no problems. You just need to make sure wiring is correct and PCM tune is also correct for the compressor type you have (fixed or variable displacement). You'll need the low and high pressure sensors depending on the setup

[kewljay223]

dude thats exactly what i was looking for. thats great news!! i talked to another member on here who is saying his is idling just fine not hooked to the new pcm. so im going to try that first and see how it goes. if i have issues, then it looks like i will be looking for a tuner who uses that software... there is a local tuner with dyno that i plan on going to once i get the turbo on, hopefully he uses that software... well see. but thanks again for that find!! i looked everywhere. i dont know how i missed that over on their sight. awesome

[fabianss357]

I was finalizing up my wiring on my 90 and have the same question. Mine isnt running yet so I dont know what it will and wont do.
I know I cant tie in a 12+ hot to activate the ac idle up when the compressor kicks in directly to the ecm, but I can wire something up for the electric fans to kick into high speed.
Most posts I see say the engine will sense the load and automatically idle up. What I am unclear of is the ecm tuning.
I see most guys running cable driven (dbc) tb where I am running a dbw tb. Is that where the discrepancy is? Are dbw ecms able to idle up where dbc ecm tunes won't? Anyone have any insight?