74 A/C Heater controller
Thread Starter
Heel & Toe
Joined: Dec 2010
Posts: 16
Likes: 0
From: oxnard ca
74 A/C Heater controller
My AC and heater controll functions are reversed on the controll plate. i.e. the AC engages when the indicator arrow shows that it's in the heater position and vise - versa. Has anyone had to deal with type of problem?
Burning Brakes
Joined: Apr 2007
Posts: 1,028
Likes: 1
From: SOUTH ELGIN IL
I have not had this one, but maybe the lines in the center console are reversed? You can pull the shifter plate, lift it out and examine the control mechanism from the underside and probably determine if that is the case.
Did you do any work elsewhere that could have caused the change (ie re-connected something opposite the way it should be)?
This would be easier if I had recently taken it apart. I did mine last summer. Sorry.
-DT
Did you do any work elsewhere that could have caused the change (ie re-connected something opposite the way it should be)?
This would be easier if I had recently taken it apart. I did mine last summer. Sorry.
-DT
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
I'm guessing the strings on the thumb wheels have stretched or slipped a little with age. Can you live with it? I would not pull the console apart to make the repair unless something else was needed.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
There are contact switches mounted to the sides of the control head that signal the A/C when to turn ON/OFF. Either the wires on these switches have been reversed or the mechanism that activates them is not working correctly. They are tricky, as one of them is spring loaded...and the spring has to be tweaked just right for the contact to 'make' at just the right point.
The Chevrolet Chassis Service Manual has good information, photos, logic diagrams for aiding your diagnosis. Before you complete work on that control head, make certain that the electrical switches are performing as needed and when needed with an ohmeter as you move the thumbwheel through its various positions. Otherwise, you might be removing it again.
The Chevrolet Chassis Service Manual has good information, photos, logic diagrams for aiding your diagnosis. Before you complete work on that control head, make certain that the electrical switches are performing as needed and when needed with an ohmeter as you move the thumbwheel through its various positions. Otherwise, you might be removing it again.
