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Author Topic: Heater & A/C blower doesn't work on high speed  (Read 23782 times)

Offline 73c10Shorty

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Heater & A/C blower doesn't work on high speed
« on: July 22, 2008, 12:34:24 PM »
So I'm still having problems with my A/C. I initially thought the switch was bad so I replaced it, but I still don't have high speed on the blower. Vile mentioned that it could be a relay. Does anybody have experience replacing this relay and possibly have a part # that I can reference?
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Offline 73c10Shorty

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Re: Heater & A/C blower doesn't work on high speed
« Reply #1 on: July 23, 2008, 12:06:07 AM »
I found the relay and removed it. I'm going to replace it with a new one and see if that fixes the problem. After doing a little more research on this issue I'm confident that the relay will fix the issue. Yep... I should have listened to Vile's recommendation. In my defense... I had already ordered the switch. :)

Here's a link to where you can order a relay in case anyone else needs one.

http://www.classicparts.com/1973-77--Blower-Motor-Cut-Off-Relay/productinfo/68-341/
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Offline VileZambonie

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Re: Heater & A/C blower doesn't work on high speed
« Reply #2 on: July 23, 2008, 04:49:42 AM »
You can get the relay at any autoparts store.
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Offline 73c10Shorty

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Re: Heater & A/C blower doesn't work on high speed
« Reply #3 on: July 23, 2008, 11:56:54 AM »
You're right. I was able to get one from my local auto parts store. Unfortunately the new relay didn't solve the problem. I still don't have high speed on the blower. Any other ideas?
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Offline VileZambonie

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Re: Heater & A/C blower doesn't work on high speed
« Reply #4 on: July 23, 2008, 12:03:09 PM »
Let's start from scratch here. I was under the impression you TESTED it. #1 check the fuse. All speeds except high speed work? I assume when you checked/replaced your switch that you checked the connections and wires? How are the connections at the relay? i posted a schematic for this in another thread.
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Offline 73c10Shorty

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Re: Heater & A/C blower doesn't work on high speed
« Reply #5 on: July 26, 2008, 06:00:14 PM »
Yes, all speeds work except for high. All of the connections and wires look good at the switch and at the relay. Which fuse would I need to check? If it's not the fuse I think I'm going to have to take it to an electrical shop and let them figure it out. Thanks again for your help.
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Offline choptop

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Re: Heater & A/C blower doesn't work on high speed
« Reply #6 on: July 27, 2008, 09:36:24 PM »
What about the fan speed control resistor? (For lack of better words) non ac shown
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Offline choptop

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Re: Heater & A/C blower doesn't work on high speed
« Reply #7 on: July 27, 2008, 09:41:07 PM »
with a/c
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Offline VileZambonie

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Re: Heater & A/C blower doesn't work on high speed
« Reply #8 on: July 27, 2008, 09:47:21 PM »
The resistor is bypassed in high speed. The wire is basically jumpered to the motor.
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Offline VileZambonie

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Re: Heater & A/C blower doesn't work on high speed
« Reply #9 on: July 27, 2008, 09:52:04 PM »
My other post disappeared too. Make sure you check the B+ to the relay you replaced. On your truck there should be a fuse from the junction block
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Offline Captkaos

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Re: Heater & A/C blower doesn't work on high speed
« Reply #10 on: July 27, 2008, 10:25:24 PM »
I had to "fix" the post so everyone could reply.....
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