I am new to the F150 world. I just bought this truck 3 weeks ago and I have several electrical problems that I can't figure out. Let me explain.


I lost my Break lights so I first went to the interior fuse box. There, I discovered that the socket that the fuse plugs into is worn and won't hold the fuse securely. I pulled the fuse box and GEM, hoping to be able to open the fuse box and repair the single socket that had the issue. I found that I couldn't do that, so I added a tiny bit of soldier to each leg of the fuse and it now holds well. Break lights now work as expected.


After reinstalling everything under the dash is when I started having other issues. The speedometer stopped working (odometer never did work, probably due to a stripped out gear), the turn signals stopped working, though the hazards still work and now, the Air Bag indicator light on the dash stays on.


On Yeah, I am also experiencing problems with the air control. No matter where I dial it to, it only blows to the windshield.


I know I have a lot of different issues here, but any assistance would be greatly appreciated.

 

Same type of thing is happening to me and I'm 90 percent sure it's the GEM I'm going to replace it

 

Your heater issue is due to a loss of vacuum somewhere. The system is run partly on vacuum so when it lacks, it switches everything to defrost just in case it sticks somewhere else, so in emergency, at least you won't fog up. Check around your battery for small vacuum lines, leaks that cause that are usually around there.

 

If your climate control is the electric one then it may be the o-rings inside of it.
Here's a guide on how to fix that.
http://www.mercurymarauder.net/forum...ad.php?t=80673

 

Going to check the GEM. I have a friend that has a computer that claims can diagnose GEM problems. I'm gonna give that a try.
As for the Climate Control issue, I don't know if it is the Electrical type of Mechanical. I guess it's time to break into that part of the dash and find out. Will update when I discover anything.
Thanks for the tips, everyone.

 

Well, I have discovered that the Turn Signals are not controlled thru the GEM, so even if I have a GEM issue, that's not what is causing the Turn Signal problem.


Does anyone know where I can Find a list of what circuits ARE run thru the GEM?

 

Let me know if your replacement works and I will give it a try. I'm just hesitant to spend money on something if I'm not sure it is going to fix the problem.

 

Just an update to the issues described above. My so and I were driving on the interstate (keeping up with the flow of traffic, since the speedometer doesn't work) and all of a sudden, the speedo started working. It appears to be accurate and consistent.


Now the next major issue is the Turn Signals. I am getting power to the switch (purple wire). Just haven't found where it "ISN'T" getting through. Any ideas or suggestions would be appreciated.

 

I hope for your sake that it's not the GEM module. There is not a single Ford dealer that stocks the part for 1997 and 1998 trucks, and two of them claim that Ford discontinued the part!!!!! It's been hot and dry in Atlanta and all of a sudden, mine now works. I'm going to have the windshield resealed, or something like that to keep it from happening again.

I'd hate to have to buy a 2010, with almost as many miles (150k) for $20,000 only because Ford discontinued that $&@/$ part!!!!!!

 

You might want to search this forum for "multifunction switch" and it just may need only contact cleaner. Had to do that to make washer pump work. And BTW, I had to replace my gauge cluster with a donor. Speed was off by 7 MPH, battery would read zero, and gas gauge magically added half a tank after driving 200 miles.