Gem problem? Or something else?
 

Hello. My 1997 f150 4.6 L is driving me nuts. I'll go and take it to work and everything works like it should. Then before I get there (20 mile trip) the windshield wipers, 4x4 control (it's mechanical on the floor) dome light, and buzzer stop working. Sometimes it will sit overnight and be fine thetnext day... sometimes it won't and will be fine days later until driven. checked the fuses and they are ok. I pulled the fuse box and gem and inspected them for water damage and found nothing leading me to believe it had been wet. Checked the fuses in the engine bay. All good. Checked grounds on firewall, under cab to frame, all there and good. Any suggestions?

All the functions you mention involve the GEM module.
Could be a rusted common ground.
You just have to chase it to conclusion.
Good luck.

Any idea what grounds I'm not seeing? I checked the ones in the cab behind both kick panels. I did find some wires to the driver's door that had been repaired by a previous owner. I'm thinking about redoing them. It's been ultra frustrating. Because of the sporadic way it comes and goes it's very hard to pin point anything.

Could be a faulty Gem, even though there is no outside signs.
If all those functions are OD, the Gem is unable to function.
Use a voltmeter to be sure there is power to the module.
Good luck.

does the windshield leak?

I've checked the windshield and the cab side of the firewall and high carpet like I've seen in other threads about water getting to the gem/fuse box. I would be out there today working on it but it's pouring rain here today. No leaks seen today when I ran up to Dollar general little bit ago. No dome lights, no dinner, no wipers, 4x4. Then when I left Dollar general it all worked. It's crazy.

Pretty indicative of an intermittent connection.
Ground or power.

Observe is any of these functions are missing with key in ACESS position.
Some of the power feeds are through the ignition switch.
Fuses 110,14 and 15 are full time feeds.
Fuse 6 and 8 are through the ignition switch.
There are two grounds behind the kick panel.
One of these locations is intermittent.

I still think its water getting in, after driving it , it warmed up and dried out some

I would agree if it didnt mostly seem to reset or come back that is over night. Im thinking ground too but cant figure out which one is bad.

Seems like It fixed. I found some rust holes near grounds behind the kick panels. I filled and patched the holes and the problems seem to go away.

So been a few weeks of intermittent wipers, dome light, dinger, 4x4. Today I found a matching gem in the local scrap yard. 35 bucks. Works like a charm. One thing I noticed is the dome light, lights on the doors and bed light are all much brighter. Dinger is much louder. Really wish I had a way to protect the gem better. Going to see if I can't make some sort of cover for it.

I would check carefully for windshield leaks, and reseal if necessary.

How was the GEM swap? I've heard they suck.

A GEM swap should be straightforward as long as you get the right GEM. There's 2wd with or without power group, 4wd with ESOF or manual transfer case, etc.

Thanks