While driving my late-model pickup truck, I pushed the button on my door handle to lower the passenger window to get a cross-breeze, but the window did not respond. This was surprising, since I frequently lower the passenger window, and I have never had a problem in the three years since I bought the truck.
So I tried the driver’s side window and it worked fine. I tried the button again for the passenger window, still nothing. I then pressed the buttons for the two rear windows, and to my surprise, they did not respond either. I checked the dash to see if there were any warning lights on, and then checked other electronics. All seemed in normal working order.
When I parked the truck, I tried the window switches on the individual doors, but no luck. None of the three other windows worked, only the driver’s window. I could not detect any sound from the individual window motors when I activated the switches, but of course the 12V DC system does not make the 60 cycle hum of a 110V AC system. I also did not see any change in the voltmeter on the dash when operating the switches. When I tried to push one of the windows down with my hands, it didn't budge. I was sure the problem was not that the window safety lock-out switch was engaged, because three windows weren’t operating, not just the rear two windows.
At this point, I assumed that a fuse had blown, although I was a bit surprised that the truck would be wired with one window separate from the other three, instead of two windows per fuse. I looked in the owner’s manual, and found that indeed there were two fuses for the power windows. The fuse box under the hood was easy to get to, the fuses were clearly labeled, and there was even a convenient fuse puller along with spare fuses in the fuse box. I appreciated the manufacturer’s thoughtfulness, and I assumed I would have the problem solved in a matter of moments.
Unfortunately, instead of solving the problem, the problem became a mystery with the potential to be an expensive repair. When I pulled the two fuses for the windows, both looked good. The fusible link was clearly visible in each fuse, and the links were unbroken. Now, instead of a simple fuse replacement, I had a mystery electrical problem to troubleshoot.
Could it be a problem with the switches in the driver’s door handle? Maybe some part of the wiring harness was faulty, either a short or an open circuit? Would I have to start pulling panels off the doors and tracing wires? Or even worse, was there a hidden problem with the electronic control unit that operates the windows and other accessories? And how would I even troubleshoot such a problem? Would special equipment be required? As a do-it-yourselfer, I missed the simpler designs that directly wire switches to window motors.
Skimming through the owner’s manual again, I looked for a troubleshooting guide for power windows, but found nothing helpful in the 700-plus pages. I was reluctant to take the truck to a repair shop because of the hassle and potential cost. I did not have a repair manual for the vehicle, so I left the problem alone for a few days. I hoped something would change to make the problem easier to solve.
After a week of pondering the problem whenever I drove the truck, I finally was able to fix the windows. Surprisingly, I was able to do it myself without equipment, no disassembly, and no out of pocket cost. Turns out that the immediate cause of the problem was, in fact, operator error.
I had inadvertently engaged the window lock-out switch, and wasn’t aware that for this vehicle, the lock-out switch affected three windows, not just the rear two. Once I realized this, I disengaged the lock-out switch and all the windows resumed working as they should.