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.
When I unplug the window motor the top left side relay clicks until i plug it back in. It also clicks when I unplug the wires from the switch itself. When i plug everything back in the clicking stops. when I roll up the passenger side it is a little slower than normal and when it is up I get a click and the door lights turn on and then go off. Not sure whats going on.
It could be but I have never heard your symptoms associated with a GEM failure. Standard GEM failure is power windows, dome lights, wipers and 4wd do not work. Any chance of water//corrosion in the power window switch?
i know the window motor works fine in both up and down. I took motor out and tested it. But when i hook it back up it doesnt work. when i hit the window up for the passenger side the motor on the driver side makes noise. I dont see any damaged wires in the door jam area. Could the gem be bad? Thanks
Pull the boot back that is covering the wiring in the driver’s door jamb and inspect for damaged wires. Do not damage the boot or you will always have problems.
could i tap into the ground wire and make up a new ground? Also I took the door panel off and when I unplug the window motor the relay clicks like crazy. It also happened when I went to take off the door panel and unplugged the wires from the back of the window switch.