A/C wire Harness
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G3GM :: G3 Tech :: Electrical
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A/C wire Harness
by 76Chevelle2Tone Fri Jul 05, 2024 11:08 pm
Does anyone know how widely across years and models the 76 Malibu A/C wiring harness was used? The GM part number seems to be "8908563". Thanks for any info.
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Re: A/C wire Harness
by 76Chevelle2Tone Sun Jul 07, 2024 12:48 pm
Surprisingly to me parts wiki says that the Sprint (I assume they mean the GMC Sprint) used the 8908563 A/C wire harness from 74-77. Was this harness that extensively used? I am having trouble finding references to it though.
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Re: A/C wire Harness
by zucchi Mon Jul 08, 2024 11:48 am
I know that '74 & '75 are identical. I know that '77 is different but I cannot personally attest to '76; I don't have the service manual for that year. Nevertheless, according to other forums, GM transitioned from the VIR to the CCOT system in 1977 and I have no evidence to dispute that.
Anyway, the VIR systems used in 1974-1976 employed a super-heat switch attached to the back of the A6 compressor. The purpose of that switch was to prevent the compressor from cooking itself if there was too much pressure in the system or a lack of refrigerant. If the head temperature got too hot, that "switch" would close to ground and short the circuit feeding current to the compressor clutch. Once closed, a fuse in the circuit would blow thus saving the compressor. The entire circuit changed when GM went with the CCOT system and the super heat switch was eliminated. I covered this in my video where I repurposed the idle stop solenoid to be an idle compensation solenoid using the current feed from the circuit which had originally gone to the super heat switch:
Anyway, the VIR systems used in 1974-1976 employed a super-heat switch attached to the back of the A6 compressor. The purpose of that switch was to prevent the compressor from cooking itself if there was too much pressure in the system or a lack of refrigerant. If the head temperature got too hot, that "switch" would close to ground and short the circuit feeding current to the compressor clutch. Once closed, a fuse in the circuit would blow thus saving the compressor. The entire circuit changed when GM went with the CCOT system and the super heat switch was eliminated. I covered this in my video where I repurposed the idle stop solenoid to be an idle compensation solenoid using the current feed from the circuit which had originally gone to the super heat switch:
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Re: A/C wire Harness
by relic7680 Mon Jul 08, 2024 1:46 pm
My '71-'77 Sprint parts manuals lists 8908563 as "75-7 Sprint w/C.A.C." description "wiring" and "HARNESS ASM., A.C. Wiring" under the 1976 Air Conditioning Electrical Systems illustration.
You will have to source this harness used, if you're looking for one.
FYI, the GMC Sprint is a rebadged El Camino, and is identical to the Malibu from the dash forward.
You will have to source this harness used, if you're looking for one.
FYI, the GMC Sprint is a rebadged El Camino, and is identical to the Malibu from the dash forward.
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Re: A/C wire Harness
by 76Chevelle2Tone Mon Jul 08, 2024 11:53 pm
Zucchi,
Yes 1977 was the change over to the CCOT system from the VIR system. I believe all A body 76s with A/C have VIR and all 77s CCOT. Corvettes may be the exception but that's outside this Forum. Yes the back of the compressor had a superheat switch.
I think the VIR system was 74-76 but that doesn't mean that the harnesses must be the same unfortunately. That's what the issue is. It seems that GMC Sprint harnesses should be the same for 74 to 77 and I assume El Camino from what Relic said . But whether Lagunas or other non Chevy A bodies used the same harness is still an open question.
Relic: Thanks for the information about the GMC Sprint. I wondered about the overlap with El Camino but good to know that the front end should be the same.
Yes 1977 was the change over to the CCOT system from the VIR system. I believe all A body 76s with A/C have VIR and all 77s CCOT. Corvettes may be the exception but that's outside this Forum. Yes the back of the compressor had a superheat switch.
I think the VIR system was 74-76 but that doesn't mean that the harnesses must be the same unfortunately. That's what the issue is. It seems that GMC Sprint harnesses should be the same for 74 to 77 and I assume El Camino from what Relic said . But whether Lagunas or other non Chevy A bodies used the same harness is still an open question.
Relic: Thanks for the information about the GMC Sprint. I wondered about the overlap with El Camino but good to know that the front end should be the same.
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