Why don't I have a anti dieseling relay or switch? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevydog66 · 10-15-2012, 10:57 PM

I have a 72 GMC with a/c and I am rewiring the whole truck with American Autowire and the a/c harness didn't come with the kit. So, I ordered a new a/c wire harness and it has a plug by the glove box for the anti dieseling relay or switch. I don't have any such thing in my truck nor have I ever heard of such a thing. Do I really need to buy one?

Square_78 · 10-15-2012, 11:28 PM

I believe those relays were discontinued in 1971 which would explain why your truck doesnt have one. Does your truck shut off when you turn the key off? If so they you dont need it. All it does is engage the AC compressor for a few seconds after turning the key off, thus putting load on the engine to kill it. Sounds like a bandaid for a bigger problem.

chevydog66 · 10-16-2012, 08:26 AM

I have a LS motor in my truck without the a/c hooked up yet. So i guess i dont even need it.
Posted via Mobile Device

GuyO · 07-04-2014, 03:52 PM

Old thread, but there was still an anti-dieseling relay in 1972. For those looking for it, it is located under the dash between the ignition switch and ash tray or heater/AC controls. It looks like the blower relay that is near the top of the air box on the passenger side.

10-15-2012, 10:57 PM	#1
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Why don't I have a anti dieseling relay or switch? I have a 72 GMC with a/c and I am rewiring the whole truck with American Autowire and the a/c harness didn't come with the kit. So, I ordered a new a/c wire harness and it has a plug by the glove box for the anti dieseling relay or switch. I don't have any such thing in my truck nor have I ever heard of such a thing. Do I really need to buy one? __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

10-15-2012, 11:28 PM	#2
Square_78 Registered User Join Date: Mar 2012 Location: Okanagan Valley, BC, Canada Posts: 1,237	Re: Why don't I have a anti dieseling relay or switch? I believe those relays were discontinued in 1971 which would explain why your truck doesnt have one. Does your truck shut off when you turn the key off? If so they you dont need it. All it does is engage the AC compressor for a few seconds after turning the key off, thus putting load on the engine to kill it. Sounds like a bandaid for a bigger problem. __________________ #teamlongbed "I refuse to go disc brakes. I actually love drum brakes. It makes for an adventure." - 50bomb 1978 Chevy shop truck - static 6/8" 1970 GMC 1500 - Accuair eLevel Resto-mod http://67-72chevytrucks.com/vboard/s...d.php?t=537497

10-16-2012, 08:26 AM	#3
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Re: Why don't I have a anti dieseling relay or switch? I have a LS motor in my truck without the a/c hooked up yet. So i guess i dont even need it. Posted via Mobile Device __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

07-04-2014, 03:52 PM	#4
GuyO Registered User Join Date: Nov 2011 Location: Kirkland, WA Posts: 343	Re: Why don't I have a anti dieseling relay or switch? Old thread, but there was still an anti-dieseling relay in 1972. For those looking for it, it is located under the dash between the ignition switch and ash tray or heater/AC controls. It looks like the blower relay that is near the top of the air box on the passenger side.

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