Climate Control Fan Switch "Off" Modification

Courtesy of Eugene Fisher

General Motors decided at some point in the production run of GMC motorhomes that the climate control fan should run constantly. I wanted the option to turn the fan off. The early models of the GMC had an off position on the climate control and this modification will implement the same function. My climate control had only a "Low" speed as the last switch position.
Several Western States GMC members recommended that the easy way to provide this off position was to remove a wire from the resistor speed connector. The connector is inside the driver side hood door to the left of the master cylinder as shown in this picture.
They recommend two methods to implement this modification. One was to bend the pin going into the connector and the other was to remove the wire from the harness. I chose to remove the wire since I did not risk breaking the pin and replacing the wire is easy if I make a mistake.
The bottom wire or slow speed wire was yellow in my case and I think it will be the same always. Remove the connector from the heater body and insert a small screw driver into the connection side of the connector at the small notch at the top of the pin to be removed. This will depress a small holding tab and by pulling on the wire you can remove the pin. Tape the wire back to the wire harness so that it will not short to any metal. Pushing the pin back into the connector body can undo the modification. This is a good time to clean the pins on the heater body and spray them with a contact cleaner. These need to make good contact for the fan to operate properly and reduce contact resistance.
The dash control now has the lowest position of the fan control as an off position. The other fan settings remain unchanged.

 Return to Technical Information

 Return to
The author is a
member of
moonlight productions  
The HTML Writers Guild
Analysis by
© 1998 by Patrick Flowers. All Rights Reserved
Revised 6/4S/98