I have a 99 Expedition with a 5.4. It recently stopped shifting into 4 wheel drive. When I turn the switch nothing happens. No relays clicking, no dash light, nothing. So far I've tested the switch and found it to be good. I have the official Ford testing procedures that consist of 58 steps covering 30 pages but I've found it to be useless as I have no knowledge of where to locate "GEM connector 248L~3/6c-82B pin8". OK, it doesn't say that exactly but it might as well. Basically I don't know where all the plugs and connectors are located and I don't have a scan tool to check the 'values'. So here's what I do know: Nothing happens. Fuses are good. My first thought would be that the shift motor is bad but since the relays aren't engaging I'm assuming that the GEM (wherever/whatever that is) is defective. I've tried to locate the relays but I can't find them. I've removed the oval piece on the dash and found 2 small relays. I removed those and their large metal mounting plate and found 3 more large relays under it. None of them appear to have the proper color wires (org/yel) to be the shift relays. Any help would be appreciated. Thanks

 

The gem module is bolted to the back of the fuse box under the dash.

The 4WD drive issue does sound like a bad shift motor. Have you probed the wires at the motor for power? If you get power to the motor but no 4WD shift, then the motor is the likely culprit. Some people have reported the motor simply jambing. They took it out, put it back in, and it worked.

 

There is no power to the motor. I did find where the relay is located thanks to another thread and tested that and found that the GEM is defective. Thanks

 

I myself am having a problem shifting into low range, It'll go into 4 high but not 4 low. Thinking it was the shift motor, I replaced that but still no go. Where are the relays for this, when I shift it into 4 high it sounds like there's some relay's around the speedo cluster however I haven't had a chance to dig into it yet. Does anyone know if there are there seperate relay's for 4 high and 4 low and exactly where these are located ? Could this also be caused by my GEM ?

 

The relay (it's a printed circuit board in a plastic case, mines beige/grey) is located around the top, rear, left side of the radio. To access it I hade to remove the panel that surrounds the dash cluster. The panel that has the headlight switch in it. This was pretty tricky as there is a screw located behind the light switch and it really wasn't made to come out too easily once installed. As for your problem with not shifting into 4 high but still shifting into 4 low. Here's the chain of events: You turn the 4 wheel drive switch and it changes the resistence of the signal to the GEM. The GEM then sends a ground signal to the transfer case shift relay and holds that signal till the GEM sees the signal from the shift motor position sensors that it has made the shift.
So, you can have a bad switch, Bad GEM, bad relay, or bad sensor in the shift motor. Sorry.

 

I called an auto parts store today asking about the shift motor relay module, and they had no idea what I was talking about. Is this a Ford specific part only ?