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Heater & A/C blower doesn't work on high speed
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Topic: Heater & A/C blower doesn't work on high speed (Read 29091 times)
73c10Shorty
Registered Users
Posts: 112
73 Chevy Shortbed
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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1973 C10 Shortbed, 350/350
73c10Shorty
Registered Users
Posts: 112
73 Chevy Shortbed
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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1973 C10 Shortbed, 350/350
VileZambonie
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Senior Member
Posts: 19174
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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73c10Shorty
Registered Users
Posts: 112
73 Chevy Shortbed
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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1973 C10 Shortbed, 350/350
VileZambonie
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Senior Member
Posts: 19174
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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73c10Shorty
Registered Users
Posts: 112
73 Chevy Shortbed
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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1973 C10 Shortbed, 350/350
choptop
Senior Member
Posts: 2476
Extended cab fanatic
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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76 C10 Choptop,76 C10 Swb
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choptop
Senior Member
Posts: 2476
Extended cab fanatic
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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76 C10 Choptop,76 C10 Swb
85 C10, 85 K10, 85 K20,86 C10,86 K10 (all extended cabs)
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VileZambonie
Global Moderator
Senior Member
Posts: 19174
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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VileZambonie
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Posts: 19174
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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Captkaos
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Posts: 18454
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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Chris Lucas
73-87chevytrucks
captkaoscustoms
squarebody
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Heater & A/C blower doesn't work on high speed