A/C fan only works on high... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Greenlee · 09-30-2008, 11:07 AM

I think i have read about this problem before, but I had no luck with a search of the forums. My fan only blows on high. It does nothing on low or medium. I replaced the fan itself about a year ago and it has been working fine until now. Anyone have any idea what the problem is?

Pyrotechnic · 09-30-2008, 11:12 AM

Sounds like the switch. Mine works in every position but high.

jchav62 · 09-30-2008, 11:14 AM

I had this same problem on my '83. I asked my brother in law, who's a mechanic, and he said it's the switch that causes these problems. I never fixed it on my old truck, but he has done a few. Replace the fan switch...

Trimman · 09-30-2008, 11:17 AM

Mine did that not to long ago. Check the resistor, it's mounted on the evaporator box. Mine was coroded cleaned it up works fine now.

Square84 · 09-30-2008, 12:29 PM

x2 check the resistor it controls the lower speeds of the fan your high speed is wired directly to a power source so even if the resistor is bad the high will still work

abebummy26 · 09-30-2008, 02:48 PM

I agree with Joe its the switch. My car did the same thing on the lower 2 speeds, one of the resistors (I think) inside it went bad.

COMP · 09-30-2008, 02:51 PM

Quote:

Originally Posted by abebummy26

I agree with Joe its the switch. My car did the same thing on the lower 2 speeds, one of the resistors (I think) inside it went bad.

they aren't in the switch on mine

f.monroe · 09-30-2008, 07:39 PM

What year truck ? My 73 Cheyenne only blows on high if the temp control lever is all the way over to cold . If you back it down a little , you feel a click and then the fan can be run in any speed . The owners manual says that this is how it is suppose to work .
Frank

Greenlee · 10-02-2008, 02:19 PM

Quote:

Originally Posted by f.monroe

What year truck ? My 73 Cheyenne only blows on high if the temp control lever is all the way over to cold . If you back it down a little , you feel a click and then the fan can be run in any speed . The owners manual says that this is how it is suppose to work .
Frank

It's a 1976 Silverado. I am planning to check out everyones suggestions this weekend and see if I can figure out what's wrong with it.

09-30-2008, 11:07 AM	#1
Greenlee Registered User Join Date: Jun 2004 Location: El Lago, TX Posts: 1,668	A/C fan only works on high... I think i have read about this problem before, but I had no luck with a search of the forums. My fan only blows on high. It does nothing on low or medium. I replaced the fan itself about a year ago and it has been working fine until now. Anyone have any idea what the problem is?

09-30-2008, 11:12 AM	#2
Pyrotechnic Registered User Join Date: Feb 2007 Location: Austin, TX Posts: 3,930	Re: A/C fan only works on high... Sounds like the switch. Mine works in every position but high. __________________ 1977 GMC Sierra Grande

09-30-2008, 11:14 AM	#3
jchav62 1962 C-10 Join Date: Apr 2005 Location: Las Vegas, New Mexico Posts: 4,978	Re: A/C fan only works on high... I had this same problem on my '83. I asked my brother in law, who's a mechanic, and he said it's the switch that causes these problems. I never fixed it on my old truck, but he has done a few. Replace the fan switch... __________________ Joseph Chavez "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4

09-30-2008, 11:17 AM	#4
Trimman Registered User Join Date: Jan 2005 Location: Hixson TN. Posts: 74	Re: A/C fan only works on high... Mine did that not to long ago. Check the resistor, it's mounted on the evaporator box. Mine was coroded cleaned it up works fine now. __________________ 82 C-10 Scottsdale LB owned since 89 350 crate vortec heads Crane 1.6 full rollers edelbrock 1406 edelbrock performer eps intake dynomax headers/flowmaster 70's BTO 700r4 level 3 custom 2 piece driveshaft 12 bolt gov loc w/3.08

09-30-2008, 12:29 PM	#5
Square84 I don't think these pills work Join Date: Apr 2008 Location: burkburnett,Tx Posts: 626	Re: A/C fan only works on high... x2 check the resistor it controls the lower speeds of the fan your high speed is wired directly to a power source so even if the resistor is bad the high will still work __________________ SQUARE84 90 SUBURBAN

09-30-2008, 02:48 PM	#6
abebummy26 Registered User Join Date: Sep 2006 Location: New Haven, MO Posts: 1,243	Re: A/C fan only works on high... I agree with Joe its the switch. My car did the same thing on the lower 2 speeds, one of the resistors (I think) inside it went bad. __________________ -Lincoln 1987 GMC S15 (soon to be a chevy clone) 2.5l, 4 speed, no ps, no pb, no ac Silence is golden, but duct tape is silver. Spoken by Cletus the hillbilly I like stickers... a whole bunch. Last edited by abebummy26; 09-30-2008 at 02:49 PM.

09-30-2008, 07:39 PM	#8
f.monroe Senior Member Join Date: May 2004 Location: Caldwell,Tx. Posts: 3,648	Re: A/C fan only works on high... What year truck ? My 73 Cheyenne only blows on high if the temp control lever is all the way over to cold . If you back it down a little , you feel a click and then the fan can be run in any speed . The owners manual says that this is how it is suppose to work . Frank __________________ Born and proudly residing in a Red State !



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