Rear Switch for Tailgate Window - Procedure

Contributed By: Bill Kelsey

The wiring for these electric lift tailgate windows is pretty simple, and if it works from the dash but not from the tailgate it is pretty certain the tailgate switch is defective.

ou will need to remove the tailgate carpetting and access panel to see the following.

Briefly, there are three wires that control the tailgate motor:

1. A red with trace wire, which provides power to the tailgate motor and defogger. This is always hot at 20+ amps. Since you can use the tailgate motor from the dash switch, this has to be intact.
2. A tan wire that runs from the dash switch through the tailgate switch to the motor. As I recall, this controls the the "down" function of the tailgate motor. Again, this wire has to be intact if the window can be lowered from the dash switch.
3. A brown wire that runs from the dash switch through the tailgate switch to the motor. As I recall, this controls the the "up" function of the tailgate motor. Again, this wire has to be intact if the window can be raised from the dash switch.

I may have the functions of the brown and tan wires reversed.

Since the dash switch and the tailgate switch share the same wiring, and the motor works from the dash switch, the problem should be in the main (keyed) tailgate switch, which you should plan on replacing (new of used), unless you can repair yours (I don't know if these are repairable -- I went the below route for a permanent fix).

You can test the tailgate switch as follows (from the 1979 TSM); note that you can use a multimeter in place of the test lamp:

Tailgate Window Switch

1. Using a 12vdc test lamp, connect one end of test lamp to ground and place probe to red with trace wire of tailgate window switch. If lamp lights, proceed to step (2). If lamp does not light, repair problem in feed [power] circuit before proceeding.
2. Place test lamp probe to tan wire of tailgate switch. Turn tailgate window switch to down position. If lamp lights, proceed to step (3). If lamp does not light, replace switch.
3. Place test lamp probe to brown wire of tailgate switch. Turn tailgate window switch to up position. If lamp lights, proceed to next test [safety switch]. If lamp does not light, replace switch.

Tailgate Window Safety Switch

1. Using a 12vdc test lamp, connect one end of test lamp to ground and place proble to brown wire of safety switch. Turn tailgate window to up position. If lamp lights, voltage is present at switch. If lamp does not light, repair feed circuits as necessary.
2. Place test lamp proble to brown wire at switch. Turn tailgate window switch to up position and close safety switch [on the driver's side of the tailgate]. If lamp lights, proceed to next test [window motor, which we know works]. If lamp does not light, replace switch.

Another alternative is to find a manual tailgate life and install it in place of the electric one. The only thing that goes bad with these is that the teeth inside the outside crank handle may eventually wear out and the crank handle have to be replaced. The electric-to- manual lift parts swap is very easy -- a couple of hours work if you take your time.

Then you can have what Jeep never sold -- a manual rear window with a defogger!

Good luck!

Bill Kelsey
Aberdeen, South Dakota
'79 widetrack Cherokee "S"