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- - AC blows on high only (https://67-72chevytrucks.com/vboard/showthread.php?t=810996)

engineer_gregh

08-24-2020 01:40 PM

AC blows on high only

My 74 blows on high when you slide the top slide to AC no matter where the fan switch is. If you move the slide to anything other than AC the fan switch works as it should. Any help or advice would be appreciated.

Bandit130

08-24-2020 02:34 PM

Re: AC blows on high only

I had the same thing till I found out from another squarebody guy. The temp slider has a slight indent just about 1/4 " to the right of full cold. So with temp slider all the way on cold, slide slightly to right till you feel a little bump. This will allow the fan to operate on different speeds. I couldn't figure it out till I found out.

kglowacky

08-25-2020 04:22 PM

Re: AC blows on high only

do these fans run all the time on low. i have a 78 i am putting together and mine is running at low all the time. not sure if this is factory as the switch says low not off

engineer_gregh

08-25-2020 04:34 PM

Re: AC blows on high only

Bandit130 that was it. Thank you.

Bandit130

08-25-2020 04:48 PM

Re: AC blows on high only

1 Attachment(s)

Quote:

Originally Posted by engineer_gregh (Post 8797907)

Bandit130 that was it. Thank you.

Your welcome.

The fan runs on low speed all the time. The switch shows LO at the bottom setting, no off. There is MED1, Med2, HI. With the help of an electronics engineer, there is a way to eliminate the low speed.

On the blower motor resistor, the 4 wire connector, remove the top wire from the connector. It eliminates the low speed.

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