First of all let me introduce myself... My name is Ray,I've been a Ford owner on and off for 30 years. Had a brand new 1996 T-Bird that I owned for 16 years, 4.6l V-8....What a great car ! I bought it for our family vehicle,no way I was getting a 4-door ! Anyway, just purchased a 1999 Expedition and seems I have a bad GEM Module from all the searching I have done. Can any one tell me what all this controls and where I might check to see if power is getting to it.
Here's what all is not functional on the vehicle;
No brake lights,turn signals,em flashers,no dome light,power windows don't work, can't adjust the mirrors,no radio. not sure about the 4wd button... and won't come out of park.
Things that work;
The headlights work and tail lights,back up lights,all instruments and panel lights work including the odometer.Power seats,door locks and adjustable brake and gas pedals all work as well....

Oh yeah there are no signs of water damage or corrosion in the fuse box or module...

Was getting ready to order the GEM Module and try it..
What do you think ?

Thanks !
Ray

 

The general answer.....

GEM module is an abbreviation for Generic Electronic Module. It is a body control computer found in ford vehicles. It controls several functions which include remote keyless entry, Interior lighting, and warning chimes and warning lamps.

 

Well none of those are working so I assume I'm on the right track ?The guy I bought it from says all was working fine a few weeks ago, and He is a friend of mine so I trust he was telling me the truth. I cant believe it needs a fuse box as well. I checked the ground wires behind the kick panel and all were tight even went through the old GEM module and re-flowed soldier on all the plug contacts......Ordered a new (used) GEM tonight. Has a return policy if it doesn't work. fingers crossed.

Ray

 

Check to make sure the accessory delay relay in the fuse box under the dash is working properly. As far as the brakes and turn signals that could be the turn signal switch being bad on the steering column.

 

okay, thanks, will do...........Keep ya posted.

 

On a further note, the tilting action of the steering column has been know to stress the wiring and pull the electrical connector out of the turn signal switch, breaking the latch on the connector in the process.

 

Okay, replaced the GEM module the relay that you suggested also the two other smaller relays,and the brake light switch. Still the same..... :-/ The wiring to the turn signal and plugs are all in tact as far as I can see. Any other suggestions ?

Thanks,
Ray

 

At any point in time, did you get out the meter and actually check anything for power? The GEM module, for example has nothing to do with the brake lights and the shift interlock.

Do you have a meter? You're going to either need to use one or to continue guessing.

 

Yes, I have a volt meter.... How do I check for voltage to the GEM ? Obviously I'm getting voltage to the fuse box ?

Ray

 

Yippee ! Fixed it ! Bad Central Junction box fuse !(under the hood) Not sure if I needed to replace what I did but all is working now !..... Only thing that doesn't work now is radio display...that I see so far. Any ideas ?

Thanks for all your help !
Ray

 

Wow! In less than an hour with the right tool you made actual and real progress without guessing. Imagine that!

Depending on the specific audio system installed, you may have up to 4 fuses in the CJB that are involved the radio system. Check them out.

 

Still factory... Thanks a bunch ! Ill check it out.

Ray

 

Is your dimmer switch for the dash lights turned up? Some radio displays dim along with the dash lights.

 

Yup it is, but no display still...........

 

Perhaps then the radio display is a bulb and it's blown?