1997 Ford F150, Power Windows Inop

This 1997 Ford F150 came in with three complaints. The power windows do not work. The wipers do not work and the interior lights do not work. Figuring that they were all related I decided to test the easiest system to access, the power windows. I pulled the driver’s side power window switch assembly up and checked for power at the light blue/black wire with the key on. No power.

I then went to the interior fuse box and removed the battery saver relay. It is the small relay second from the top left corner.

I checked for ignition power on the lower right terminal, 12 volts, good.

I checked for ground at the upper right hand terminal by first placing one lead of my voltmeter to a positive battery source, 0 volts, bad. That in itself is enough to show that the GEM module is faulty but I also looked at GEM data with a scan tool and saw that internal system voltage was 22 volts. Hard to do with a 12 volt battery. Diagnosis of a faulty GEM module. To see how to replace the module please click here.

This is the reading with a new GEM module across terminals 85 and 86. Just like it should be 12 volts. Another important note is that I asked the customer about water leaks on this side of the truck and also closely inspected everything as I disassembled looking for signs of water intrusion. Water leaks are a big problem with these modules.

Again with the new GEM installed there is now power on the light blue/black wire.

In case you have not already figured it out if the windows had to be operated to raise a downed window you could do one of two things if there is no power at the light blue/black wire. One, you could apply 12 volts to this wire with a jumper wire. Two, you could jumper terminals 87 and 30 together at the battery saver relay. The second will also test the wiring in the door jamb as well.

122 discussions on “1997 Ford F150, Power Windows Inop”

  1. Although the GEM will more than likely be your problem your thoughts of how the system works are a little bit off. The GEM is looking for the door to open in order to disengage the relay. Sometimes just opening the other door will send the correct signal to the GEM. That is more effective on vehicles that are prone to door ajar switches failing. Regardless the GEM should turn the accessories off after about ten minutes with the ignition switched off.

    1. I see. I just figured after ten minutes of truck powered down wether open or close it would shut down. Driving home from work I had 4×4 lights come on and off and each time I stopped and cut the truck off and take key out I am able to operate all controls in the cab. Something else I am now confused is I took out the relay that was making all the noise which was relay one for the dome light and kept it out…well it came on the way home and now will not go off…I am confused as ever…my truck is possesed…lol

  2. Great Site! I have a 98 F150 4×4 that during really cold days it seems none of my electronics cut off when I turn truck off and take key out. I can still operate window, turn air blower on and I noticed the dome light going dim and bright but will not shut off. There was a loud buzzing coming from the number one relay which is the for the overhead light. I removed the relay but the other electronics are still functioning with truck off. I thought from reading your post that maybe the GEM was not seeing door ajar but after 30mins of door shut still the same thing????

  3. Hey my ’97 F250 Light Duty (F150 with 7 lug package) has power mirrors but they aren’t working. I replaced the mirrors yesterday with new tow mirrors and still nothing. Over the summer my alarm started going off so I unplugged the fuse to the alarm after dealing with it for a month and it stopped. Also noticed the green with purple stripe wire under the dash had been cut. Any help would be greatly appreciated!

  4. What you refer to as the #1 relay is in fact the interior light relay. The battery saver relay has to be installed and working before power will be on that terminal. The battery saver relay and the contacts of the interior light relay are powered from fuse #14 in the interior fuse box.

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