Electric Tailgate Troubleshooting

One common problem with FSJ's is the rear window in the tailgate. Those with an electrically opperated version will eventually have some part of the circuit fail, requiring them get in and fix it. Below are three digrams, the stock setup, a setup with the tailgate switch bypassed (in cab switch will be only way to open/close the gate window), and a safety switch bypass (for use when the safety switch fails, making it to where the gate wont open from either switch).

Note: Wire colors may vary from year to year.

Stock Wiring Configuration


Tailgate Switch Bypassed


Safety Switch Bypassed


Knowing Which Bypass to Use:

Knowing which bypass to use requires a bit of knowledge and troubleshooting, a multimeter is required for most troubleshooting.

If both the inside and tailgate switch no longer function:

1: Verify the window motor is getting power using a mulitmeter set to VDC. When either switch is used, the motor should receive 12VDC. If the motor gets 12VDC, but does not opperate, then the problem is most likely a bad window motor. If the motor receives low or intermitent power, check all wiring and grounds to be sure there are no shorts or high resistance connections. All grounds should be clean and free of rust and/or corrosion. If the motor receives no power at all, check all wiring to verify there are no shorts or breaks in the circuit. If wiring checks out, proceed to step two.

2: If one switch works but not the other, move on to step three, otherwise the next part of the circuit to test is the safety switch. The purpose of the safety switch is to allow window opperation when the tailgate is closed, and to prevent opperation when the tailgate is open. The safety switch is in the ground circuit for the tailgate. If the gate is open, no ground is available for the window motor, thereby preventing opperation. To test functionality, set your multimeter to Ohms, and measure from each contact on the switch while the switch is depressed. The reading should be close to zero Ohms. If the reading is high (anything over 5 Ohms or so) then the switch is bad. Either it has become internally corroded, or is mechanically broken. In the case of this, either replace the switch if a working one can be found, or bypass it used the above mentioned 'Safety Swith Bypassed'. If the switch measures out ok, it is also possible that the tailgate switch has failed. It is inline between the dash switch, and the safety switch. Step three tells how to verify if the dash switch is working. If it is working, but the window does not opperate, than either the wiring/connections between the two is at fault, or the tailgate switch has failed. If the wiring checks out, then the tailgate switch is at fault. It should be either replaced, or bypassed as the above diagram 'Tailgate Switch Bypassed' to bypass the switch.

3: If the tailgate switch works, but not the dash switch, than the issue is most likely a bad dash switch, or the wiring that goes between the two. In this case, the wiring and the connections should be checked over and if breaks or bad connections are found, repaired. If the wiring checks out, then the dash switch should be checked. This can be done by using your multimeter set to Ohms, and measuring from the 12VDC input, to the 12VDC output while the switch is depressed (you can also use the meter set to VDC and measure for voltage, two of the three terminals should have 12VDC when the switch is depressed). This should read close to zero Ohms, if not, verify you are measuring between the correct terminals, otherwise the switch most likely needs to be replaced.

There are other reasons that can prevent gate opperation, such as: No 12VDC to the switches, mechanical problems with the window opperation, etc. But the above should give a starting point for those with one of the above issues.

Writen by Brandon Smith and Jim Baker

Feel free to post in the FORUMS with any questions regarding this write up.