A/c and non a/c harnesses basically the same? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

nyncompute · 08-26-2010, 10:21 AM

I'm looking to replace my wiring harness in the 72. I'm going with a factory unit. Are the harnesses interchangeable, or is the a/c control to compressor etc made special for these trucks??

ChevLoRay · 08-26-2010, 12:09 PM

I got my harnesses through one of the vendors on here, in Washington. Seems it was Wes. The AC harness was an additional harness, but different from a non-AC harness. All of my harnesses are from M&H Electrical Fabricators, and their web address is: www.wiringharness.com (I believe). Look at their site and you can find all you need to know about what is the same and what is different.

Site address is good.

There is a difference in the harnesses. AC harness, with heater, is $108. Heater harness (w/o AC) is $21. That's a big difference, but at least you know that the difference is also more than monetary.

JimKshortstep4x4 · 08-26-2010, 12:16 PM

All of the original harnesses that I have seen are set up so that the AC part can be easily separated from the regular under dash harness. It is a matter of switching the power wire to the AC motor switch and plugging in a power feed for the relay. There is a gray wire for the extra bulb in the controller that has to be plugged in to the fuse panel on some of the ones that I have see.

Jim

nyncompute · 08-26-2010, 12:22 PM

Got it guys. Thanks so much for the input

**JMac11** · 02-01-2011, 09:22 PM

So you pull the power lead out of the heat only circuit and plug it into the AC Harness??

**JMac11** · 02-02-2011, 04:51 PM

Top!! Anyone??

08-26-2010, 10:21 AM	#1
nyncompute Registered User Join Date: Nov 2004 Location: Southern Nevada Posts: 532	A/c and non a/c harnesses basically the same? I'm looking to replace my wiring harness in the 72. I'm going with a factory unit. Are the harnesses interchangeable, or is the a/c control to compressor etc made special for these trucks?? __________________ 1972 K-10 SWB Cheyenne

08-26-2010, 12:09 PM	#2
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: A/c and non a/c harnesses basically the same? I got my harnesses through one of the vendors on here, in Washington. Seems it was Wes. The AC harness was an additional harness, but different from a non-AC harness. All of my harnesses are from M&H Electrical Fabricators, and their web address is: www.wiringharness.com (I believe). Look at their site and you can find all you need to know about what is the same and what is different. Site address is good. There is a difference in the harnesses. AC harness, with heater, is $108. Heater harness (w/o AC) is $21. That's a big difference, but at least you know that the difference is also more than monetary. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was. Last edited by ChevLoRay; 08-26-2010 at 12:12 PM.

08-26-2010, 12:16 PM	#3
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: A/c and non a/c harnesses basically the same? All of the original harnesses that I have seen are set up so that the AC part can be easily separated from the regular under dash harness. It is a matter of switching the power wire to the AC motor switch and plugging in a power feed for the relay. There is a gray wire for the extra bulb in the controller that has to be plugged in to the fuse panel on some of the ones that I have see. Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC Last edited by JimKshortstep4x4; 08-26-2010 at 12:18 PM. Reason: added wording

08-26-2010, 12:22 PM	#4
nyncompute Registered User Join Date: Nov 2004 Location: Southern Nevada Posts: 532	Re: A/c and non a/c harnesses basically the same? Got it guys. Thanks so much for the input __________________ 1972 K-10 SWB Cheyenne

02-01-2011, 09:22 PM	#5
JMac11 Registered User Join Date: May 2005 Location: Tallahassee Fl Posts: 773	Re: A/c and non a/c harnesses basically the same? So you pull the power lead out of the heat only circuit and plug it into the AC Harness??

02-02-2011, 04:51 PM	#6
JMac11 Registered User Join Date: May 2005 Location: Tallahassee Fl Posts: 773	Re: A/c and non a/c harnesses basically the same? Top!! Anyone??



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