The windows, mirrors, interior lights, and wipers don't work on my 97 F150 4x4. I have been driving with a bad heater core which may have blown something else. I checked the fuses, but thats not it, I'll look into the GEM thing. This is the second time that heater core went bad.

Thanks for any help,
Doug

 

Definately check the GEM Module. Anytime there is multiple electrical problems in the cab , that is a good place to start. It doesn't take very much moisture to screw them up. Was the heater core leaking into the cab?

 

The leak is dripping out and maybe towards the condenser (?). I had a lot of humidity and vapors hitting the windshield, so I put a towel over the vents causing it to probably back up. Oh…it was also raining when it went out. I disconnected the battery for twenty minutes and noticed the interior cab light came on for a second then and a click under the dash. I’m outside now with a blow dryer to see if that will help. Is the GEM the box behind the interior fuse panel?
I’m running in and out to check this post for ideas.

 

Do you have an air compressor? If so I would use a long air nozzle(I have one over 3 feet long to get into hard to reach places) to blow out excess water. Of course if the water has gotten ito the inside of the GEM module the air won't help. I would remove it and open it up to dry it out. When you put it back it use some RTV or silicone caulk at the seams to keep future water out. This is a major problem for Ford.

 

You’re probably correct about opening the GEM, but I took a blow dryer to it while still mounted to the fuse panel. Everything works again. I was going to try the sealer that you let dry for 24 hrs to see if that seals the heater core again until I can get to time to replace it.

 

There is some two part sealant(like epoxy) that comes in a roll at the local hardware store. It usually has a dark core and light colored outer ring around the core. You cut off the amount you need to make the repair and knead the two parts together in your fingers until the colors mix then you apply it to the hole in the heater core. I used this stuff on a large dump truck raditor and it's still holding. You have to get a clear look at the hole where you have the leak to be able to repair it properly which isn't always easy under the dashboard.