AC Problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Hook'em · 08-30-2004, 02:22 PM

Wanting to see if anyone had any ideas. Twice in the last two weeks my AC stopped blowing. I checked the fuse the first time and it was OK, then started the truck and everything was working again. Today, while running errands at lunch, I got back into the truck and no AC. The fan/blower is not running at all.

My initial thoughts: could be a switch issue, could be a wiring issue (short, etc.).

Any thoughts as to what could be causing this intermittent problem. It is to damn hot for no AC.

1971LT1SWBPOSI373 · 08-30-2004, 02:36 PM

blower relay????

Bobalouie · 08-30-2004, 02:57 PM

Mine does the same thing. It sounds like the fan speed switch. At least that is what is wrong with mine. They are cheap, and you can get them almost anywhere.

Hook'em · 08-30-2004, 06:22 PM

I pulled this off just a minute ago. Is this the fan speed switch that may be my problem. If so, then I am going to the auto parts store to find a replacement.

red71cheyenne · 08-30-2004, 07:32 PM

Ya, mine does the same thing and its the switch going bad. Have you noticed the ends of the wires being a little burnt? I still can't figure out why mine does that. Even if I replace the switch, it doesn't take very long before it does it again. Good luck, Jeff.

chickenwing · 08-31-2004, 01:44 AM

I had a very similar problem. Turns out the blower relay has a grounding issue. The ground for the relay uses a ground strap. The ground bolts from the relay mount to a chassis ground. The relay is mounted to the plastic ac case. The relay mounting screw had been over torqued and would no longer keep the ground strap tight enough against the relay to provide a constant ground. I went to a relay with a ground terminal. It has 5 pins instead of 4. Bought it from Kragens. GP Sorensen part # AC11. Your switch looks fine from here. When my switch went out it had plenty of arcing on it. Hope this helps.
Rich

08-30-2004, 02:22 PM	#1
Hook'em Senior Member Join Date: Jul 2004 Location: Round Rock, Texas Posts: 858	AC Problems Wanting to see if anyone had any ideas. Twice in the last two weeks my AC stopped blowing. I checked the fuse the first time and it was OK, then started the truck and everything was working again. Today, while running errands at lunch, I got back into the truck and no AC. The fan/blower is not running at all. My initial thoughts: could be a switch issue, could be a wiring issue (short, etc.). Any thoughts as to what could be causing this intermittent problem. It is to damn hot for no AC. __________________ Hook'em

08-30-2004, 02:36 PM	#2
1971LT1SWBPOSI373 Registered User Join Date: Mar 2002 Location: Springfield, VA Posts: 460	re blower relay???? __________________ 1971 Shortbed 350/350 w/ Posi-traction 3:73's 1996 Chevy Silverado TJ in Springfield, Virginia Likes old Chevy trucks Drinks Miller MGD

08-30-2004, 02:57 PM	#3
Bobalouie Fetzer Valve Technician Join Date: Jun 2003 Location: Stillwater, OK Posts: 205	Mine does the same thing. It sounds like the fan speed switch. At least that is what is wrong with mine. They are cheap, and you can get them almost anywhere. __________________ 1972 Chevy K10 SWB

08-30-2004, 06:22 PM	#4
Hook'em Senior Member Join Date: Jul 2004 Location: Round Rock, Texas Posts: 858	I pulled this off just a minute ago. Is this the fan speed switch that may be my problem. If so, then I am going to the auto parts store to find a replacement. Attached Images __________________ Hook'em Last edited by Hook'em; 08-30-2004 at 06:28 PM.

08-30-2004, 07:32 PM	#5
red71cheyenne Back in the sticks Join Date: Jan 2001 Location: Fordland, MO Posts: 3,188	Ya, mine does the same thing and its the switch going bad. Have you noticed the ends of the wires being a little burnt? I still can't figure out why mine does that. Even if I replace the switch, it doesn't take very long before it does it again. Good luck, Jeff. __________________ 1971 Cheyenne C-10 w/700R4 and Tuned Port Injection 1969 K5 Blazer w/Tuned Port 2010 2SS/RS Flaming Orange Camaro 2011 K1500 Suburban 2014 K1500 Pickup 2008 Nissan Altima? The wifes' hoopty

08-31-2004, 01:44 AM	#6
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	I had a very similar problem. Turns out the blower relay has a grounding issue. The ground for the relay uses a ground strap. The ground bolts from the relay mount to a chassis ground. The relay is mounted to the plastic ac case. The relay mounting screw had been over torqued and would no longer keep the ground strap tight enough against the relay to provide a constant ground. I went to a relay with a ground terminal. It has 5 pins instead of 4. Bought it from Kragens. GP Sorensen part # AC11. Your switch looks fine from here. When my switch went out it had plenty of arcing on it. Hope this helps. Rich __________________ The truck... you hear that? No really, you did hear that?!!!



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