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.
OK, battery was good. Checked the fusible links, found one blown–it was the “Trailer Tow Battery Charge”. Replaced blown fuse, disassembled the terminal connections and cleaned them well (one was pretty loose). Put it all back together and it fired right up. Don’t know if it was the fuse or the loose terminal, just happy to have a way to get to work come Monday. Thanks for your time. Its cool that you take the time to maintain this site. I checked out your blend door replacement posts–will tackle that some day when I get to feeling adventurous. Thanks again for your site.
The two jumper cable clamps coming in contact with the just the hood or each other should not have caused any issues except for arc marks and possible burns on the contact area. The net effect would be equivalent to a starter drawing too many amps. Now if they contacted something else, that would be a different issue. The very first thing that I would do is to check to make sure that battery is fully charged and all of the terminal connections are good. Including where the cables enter the battery terminals. Nest check the fusible links at the starter relay.
First of all, this is a very cool blog, great information!
Here’s my story: We all jumped into my wife’s car to head over for some turkey with the inlaws Thursday and the car battery was too low to start (damn kids left the lights on). So I jump into my 1999 F150 and proceeded to jump the car. While jumping the car, the hood of the truck came down and I assume created a short across the battery terminals by coming in contact with both battery jumper clamps at the same time. Now the truck won’t start. The battery saver relay is clicking nonstop even with the keys out. Disconnected the battery for a while, reconnected, no change. I’ve checked the obvious fuses and relays and found nothing. Went to roll up the window, got it 1/2 way up then it stopped, now no windows work. Help!
Thanks so much for your reply. I am leaning toward the GEM. i had a buddy who worked for a ford dealer run a computer check for me just to see if it showed anything last year, and he said there was a code for the windshield wipers with the GEM back then, but i was having no issues back then either
The light blue/black wire should have power on it with the key on. I would suspect that you have either a broken wire in the driver’s door jamb wiring, the one touch auto down relay is faulty or there is GEM issue. Assuming that the window does have the auto down feature.