I have a 1991 GMC pickup truck. The bar control that determines hot or cold temps will not change from cold to warm. The control itself seems to work. I have been told that this bar controls an electric motor that does the actual switching from cold to warm. Is there anyway to make the switch from cold to warm manually

SOURCE: Fan speed switch only works on #5

Call your local GMC Dealer and see if they have the climate control panel in stock. What happens is the circuit board on the back of the panel shorts out. The panel comes as an assembly and is very easy to replace. Don't go with a wrecking yard piece. I made that mistake once and it didn't work either. I got one from the Chevy dealer and it worked perfectly.

SOURCE: 2004 GMC Yukon Denali

My wife had same problem in 2005 yukon. Turn both temperture controls on dash all the way as warm as they will go, Wait about 1 or 2 mins and turn back to coolest setting. Cleared our problem right up. Do this with car running and air on.

joecoolvette

• 5660 Answers
• Posted on May 11, 2009

SOURCE: no brake/hazard lights,have running/turn signal lights

Suggest you change hazard flasher 'can' first, then go to the hazard switch. I'm betting it's the flasher can.

SOURCE: 2000 gmc sierra 1500 5.3 v8. a/c heater control problem

your heat/cool and vent selection options are controlled by engine vacuum through small clear tubes attached to the rear of your climate control interface. Other vehicles have small steel pull wires that operate the desired changes. You might try removing the trim and any fasteners affiliated with the interface/console. GENTLY pull outward and look to see if any of these tubes are pulled off or cut/damaged. Did anyone recently install a new stereo in the vehicle? If so, the vacuum tubing and or pull wires that change your outlets could have been damaged when the stereo unit was pushed into place. Hope this helps

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SOURCE: 1990 GMC Sierra 1500 pickup. Windshield wipers, Cruise Control

May want to look at replacing the wiper circuit board.It is located on the firewall adjacent to the wiper motor and has a some what square black cover with 3 torx screws and wireing harness pluged into the side.We had a truck that every time you washed it the wipers would stay on until it dryed out.You can try removing it and spaying it down with contact cleaner just watch the brease on the two contact tips.Well hope this helps.