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.
I have a friend that needs to replace the GEM module in their 97 Ford F-150, but they don’t have the money to replace it yet. Everything works except the Windshield wipers and dome lights. Is it a big deal to leave the GEM module the way it is until they have the money?
It sounds as if you may have broken wires in the driver’s door jamb wiring. You can usually slide the rubber boot back and inspect the wiring for damage.
Oh I’m so glad I seen this! Your information and pictures have been a huge help here! Only problem is I’ve tried everything (I think) and nothing works.
97 F150 4X4
Problems That all started around the same time
1)O/D light flashes on and off (changed two sensors, VSS on rear diff, and another on transfer case)
2) drivers power window doesn’t work. With door closed hit switch up nothing down relay clicks (relay replaced same problem) door open hit the switch up and relay clicks non stop and interior dome lights flash on off in the same pattern as the relay click.
Door panel is off if I unplug the drivers side plug from the switch I have the relay dome light clicking non stop till I plug it back in, same as unplugging the motor harness.
I followed your amazing description and pictures today and fairly easily changed my gem module. Sadly still have the same issues.
Any direction at all from here would be awesome! Thanks
Those symptoms are not typical for a Gem issue. Can you be more specific in your description of the problems?
97 f-150 4.6l Problem started yesterday that headlights and AC doesn’t work. When I turn them on turn signal doesn’t work.