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 don’t think that vehicle has the GEM integrated into the blower system. I would start by testing at the blower motor connector to determine which signal was missing, power or ground. My gut feeling is the ground signal will be the problem and I would be looking for a poor body ground somewhere.
good evening sparky, 01 ranger no heater fan, at first when in reverse or hi beams on, the airbag light intermittently goes on/ off I jumped the power relay and it works, so i jumped the wires with tracers in the heater area control switch, it worked as normal, but would then make the signal flasher click(buzz), gem module again? I did try a new heater area control((also fan off) not the fan speed)switch
it was the GEM as well as the fuse box, both were full of water, got the customer to change the windshield as well.
next one is 01 ranger airbag light intermittant then one day fan wont work when on high beams or in reverse, the cause is the switch for the heater placement ie defrost floor etc, just for anyone looking for these syptoms
I would suggest moving on to the blower issue as it may be simpler to diagnose.
I have all of these symptoms and replaced the GEM with one from a salvage yard and it still does not work. What other things could be causing this. The front blower does not work and the driver door lock broke and fell into the door compartment about a month ago. Could it be as simple as that relay or a wire got broken in the door panel when the lock broke?