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AC fan wont work on high

jchitwo

By jchitwo
in Ask A GM Technician

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jchitwo Enthusiast

jchitwo

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Ok so I'm looking for a little help, I have a 78' 4x4 pickup, It's given me many years of good service and ice cold AC. I recenly went to turn it on and flip it over to high for the fan setting and the fan basically shuts off. it works well on all the other settings. I asked my dad who purchased this truck new, he said it's happened twice before and the dealer repaired it each time, unfortunalty it's been about 17 yrs since he last had the problem. I've heard this may have been a common issue with these trucks and I was wondering if anyone had any insight as to what this might be. I replaced the switch, the fan motor, and the relay. So I'm assuming that those being new are not the problem. Any suggestions just short of putting in a fused direct toggle to the fan would be appreciated. Thankyou, Jesse

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted

Yikes, I don't know if I remember how it works on a '78!

 

Seems to me there was a main power feed with an inline fuse in it under the hood, over on the right side. But jeez, I may be thinking of a car or who knows what. :driving:

 

I'm afraid I'm not going to be much help on this one. If I could look at it, I could probably figure it out without too much difficulty, but trying to pull that stuff up from memory is hard.

jchitwo Enthusiast

jchitwo

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Yikes, I don't know if I remember how it works on a '78! 

 

Seems to me there was a main power feed with an inline fuse in it under the hood, over on the right side.  But jeez, I may be thinking of a car or who knows what.  :driving:

 

I'm afraid I'm not going to be much help on this one.  If I could look at it, I could probably figure it out without too much difficulty, but trying to pull that stuff up from memory is hard.

 

 

 

 

thankx soo much for the quick reply, I'll take a good hard look at it this afternoon and see if that's the case, I seem to remember a fuse somewhere over there...

Jesse

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