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.
It sound like you have eitehr a relay or GEM problem. Please look on the left side bar for the “GEM” link. You should find the answer there.
I have an f150 97 and with the ignition switch unplugged the radio and heater fan still have power, as does the airbag light, the interior light comes on or stays on intermittently. It has no other power options to test, nice site BTW!
Just did a 1997 F150 with intermit power window (drivers) slow (pass) window. Was a broken ground wire in harness between door and pillar. The wire is the large black one. Easy to just take door off to get at.
I have seen problems with the blower motor not turning off related to water damage in the GEM. Have not experienced the rest but I would assume it may be possible. One would have to look at specific wiring diagrams to see if there is a link to the GEM.
could this also cause probs with other circuits? heater blower staying on ,speed sensor code, 4×4 light flashing