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.
Hi Sparky, I bought a 1997 F-150 and when i bought it, the turn signals would not work, and all dash lights besides the radio would not work. and after a car wash my door locks had a mind of their own. Well it was suggested to replace the GEM module, so i purchased a used one and replaced it. The ‘new’ one still had no turn signals and this time it would not start and i no longer had headlights. So i took off the ‘new’ GEM and put the old one back on. It started back up, but everything was still the same but only this time the head lights would not come on. Radio, Dome light, windows and door locks all work (besides pass. which i believe it was motor it self, or something i still have to look into it. but I’m pretty stumped, and not sure what the problem could be if you could please Help!
Hi Ranger Owner,
What have you been told is no significant drain (the actual reading)? If the test was done correctly and there is less than a .05 amp drain, monitored over a lengthy period of time, that would point to a faulty battery.
re ranger owner
the fuses have all been checked no significant draw found. that est was performed by two different mechanic shops. the battery is new, the alternator is new. from what i can assume i is something that needs power at all times. i am puzzled. the only thing i have had done was the back glass was resealed about a month befor this happened. he did not remove the headliner just took enough stuff off to get it out of his way.any other suggestions
Hi 2003 Ranger owner,
I would back up and start checking at the battery for a drain condition. Using an amp meter connected in series between the negative battery terminal and the negative battery cable. Note the size of the drain and work you way through the fuses to find the drain.
You would need to check the one touch down (auto) relay and associated wiring.