A/C Wiring - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kevinc · 06-14-2012, 12:54 PM

I started reworking my wiring harness for my 5.3L swap. I have all the wires pulled that I don't need from both computer connectors and I started going thru the C2 under hood fuseblock connector.

I plan to eventually install air conditioning into our truck, but it will probably be an under dash unit and I plan to use the stock 5.3L A/C Compressor. There are are several wires for air conditioning built into the harness. Are any of these wires worth keeping if I plan to use an under dash unit or should I pull them out?

Thank you,
Kevin C

gringoloco · 06-14-2012, 08:45 PM

Yank em. You might want the signal wire so that the PCM can adjust idle with the compressor running, but it's not necessary.
Posted via Mobile Device

**TR65** · 06-14-2012, 09:17 PM

As Gringo says, if you have an AC request line it is convenient to use it to let the ECM turn on the compressor and control the fans, idle etc.

My LS2 didn't have an AC request (comes from the BCM). But it had an AC pressure sensor. I hooked that up and the ECM is happy to control the fans based on the high side pressure, so the fans only run when they have to, even though it doesn't have an AC request.

Good luck,

TR

Custom 68 · 06-15-2012, 04:09 PM

Guys more on this if possible
I purchased a painless harness for my swap several years ago and it hs an ac request line for the idle and all, I cant seem to get it to do anything and I would like it to adjust the idle up some when teh AC is on. I wonder if my tune does not have that turned on? Do you know is this line get 12 volts or a ground?

06-14-2012, 12:54 PM	#1
kevinc Registered User Join Date: Mar 2007 Location: Waxahachie, TX Posts: 195	A/C Wiring I started reworking my wiring harness for my 5.3L swap. I have all the wires pulled that I don't need from both computer connectors and I started going thru the C2 under hood fuseblock connector. I plan to eventually install air conditioning into our truck, but it will probably be an under dash unit and I plan to use the stock 5.3L A/C Compressor. There are are several wires for air conditioning built into the harness. Are any of these wires worth keeping if I plan to use an under dash unit or should I pull them out? Thank you, Kevin C __________________ 1988 C1500 Regular Cab, Long Bed, 2WD.

06-14-2012, 08:45 PM	#2
gringoloco A guy with a truck Join Date: Sep 2005 Location: Germany, for now Posts: 5,921	Re: A/C Wiring Yank em. You might want the signal wire so that the PCM can adjust idle with the compressor running, but it's not necessary. Posted via Mobile Device __________________ -Chris Instagram _elgringoloco_ '70 Short-Wide How to: Ruin a perfectly good C10 ‘70 Blazer ConversionHow To: Ruin a Perfectly Good 4wd '72 Highlander How To: Ruin a Perfectly Good K/5 (SOLD) '72 Blazer 2WD How to: Ruin a perfectly good Blazer (SOLD) '05 Yukon Daily Driven (not so stock) Yukon (SOLD) ‘07 Yukon Denali (daily) Members met list: SCOTI, darkhorse970, 67cheby, 67cheby'sGirl, klmore, porterbuilt, n2billet, Fastrucken, classicchev, Col Clank, GSFMECH, HuggerCST, Spray-Bomb, BACKYARD88, 5150, fine69, fatbass, smbrouss70, 65StreetCruiser, GAc10boy

06-14-2012, 09:17 PM	#3
TR65 Senior Member Join Date: Nov 2007 Location: Greenville, SC Posts: 873	Re: A/C Wiring As Gringo says, if you have an AC request line it is convenient to use it to let the ECM turn on the compressor and control the fans, idle etc. My LS2 didn't have an AC request (comes from the BCM). But it had an AC pressure sensor. I hooked that up and the ECM is happy to control the fans based on the high side pressure, so the fans only run when they have to, even though it doesn't have an AC request. Good luck, TR __________________ 1965 C10 SWB Fleet Two owner LS2 Swap Thread http://67-72chevytrucks.com/vboard/s...d.php?t=413880

06-15-2012, 04:09 PM	#4
Custom 68 Registered User Join Date: Nov 2001 Location: Springfield, MO Posts: 2,939	Re: A/C Wiring Guys more on this if possible I purchased a painless harness for my swap several years ago and it hs an ac request line for the idle and all, I cant seem to get it to do anything and I would like it to adjust the idle up some when teh AC is on. I wonder if my tune does not have that turned on? Do you know is this line get 12 volts or a ground? __________________ Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!"

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