Drivers side door and dash electrical help needed

[walt88]

This one has me baffeled...and I will try to explain....

I have a '98 ford F150 extended cab with the 4.6 l engine. It has 130K miles.

I have this intermittent problem that started with the drivers side window. The window would not go down and I checked the switch, fuses, schematic, etc. The right side operated just fine and I could find nothing else wrong. The only other unusual occurrence was that the buzzer now sounded when the door was open, even though the keys were not in the ignition. However, as soon as I turned the ignition back on ( I had it off when checking fuses , etc) everything worked fine again. At the time it had rained and I attributed the problem to something in the door wiring getting wet, and sure enough I had no more problems as the weather cleared up. I don't know if it is coincidence or not, but as the weather got damp again the problem has come back. Now almost everytime I get in the truck as soon as I have driven a mile or so the drivers side window will not operate. Also now the speedometer will intermittenly stop working and go to 0. The tach works fine. And again as soon as I stop, turn off the engine, and restart it everything seems to work fine again for a whle, sometimes only a minute, other times for as long as 10 miles.

Any clues? or do I have a little gremlin?....any help would be appreciated.

WALT

[Franklin2]

A lot of these trucks had small windshield leaks that run down the inside firewall, and get the GEM module and fuse box wet. The GEM module controls the dome lights, buzzers, door locks, and power windows. Look on the inside firewall area and see if you have any wet stains and corrosion on a box with a lot of wires and the fuse box area.

[walt88]

Dave,

Thanks ! I think you are absolutely correct. The drivers side floor mat is damp from water leaking in. How can I fix the problem? I can't tell exactly where it is coming in. Can I put some RTV along an outside seam? Can I temporarily stuff a towel under the dash to keep more water from coming in until it gets dry here in Calif?

Thanks...... WALT

[BPofMD]

Actually, the leak is really in FRONT of the windshield at the airvent intake. The weatherstripping there would fold over and allow water to seep by and go in either thru the vent or go around and enter the left or (maybe both) right areas near the door seals. This also happens to the 93-98 FoMoCo cars! Ford/Lincoln/Mercury. I have a 97 Mark VIII and fixed it by replacing that weather stripping and replaceing the fasteners in front of the windshield. I would have PUDDLES in the passenger footwell.

[Franklin2]

I would get a waterhose and see if you can figure out where the leak is, I always heard it was the windshield. If you go to the auto parts store, the have a special RTV sealer for windshields that is "runny" and I have had good luck with it sealing the windshield.

[walt88]

I continue to have problems. After first drying out under the dash everthing SEEMED to OK for a while. I put a tarp over the windshield to try to keep everything dry but the battery continues to drain and there are interrmittent problems with the wipers, window, radio, speedometer, etc.....

I have spent a lot of time reading posts on the GEM module and am fairly convinced that it is the the culprit. So I have a couple of questions.
1) Where exactly on my '98 F150 is the GEM module and what does it look like? 2) If I get it dried out and will everything probably be OK or can it be that the module itself is damaged and or was damaged by getting wet?

Thanks for any input........WALT

[Franklin2]

It's a big black box, and I believe on your model it's under the dash, to the left of the brake pedal.

[projectSHO89]

Originally Posted by Franklin2

It's a big black box, and I believe on your model it's under the dash, to the left of the brake pedal.

The GEM module is mounted in the same place on all 97-03 F-series - on the upper (back) side of the fuse box.

Steve