4x4 Inop
Senior User
Joined: Dec 2011
Posts: 484
Likes: 0
From: Rockland Ontario
Here are some examples "read' from the GEM module....
the codes from the GEM/CTM areas follows
B1359
P1820
P1828
P1865
P1876
B1359 is for ign run/accesory circuit failure. for codes p1820, p1828, and p1865, the first step wants you to check the function of the ign switch. We may have an issue here since all these codes have this in common.
the codes from the GEM/CTM areas follows
B1359
P1820
P1828
P1865
P1876
B1359 is for ign run/accesory circuit failure. for codes p1820, p1828, and p1865, the first step wants you to check the function of the ign switch. We may have an issue here since all these codes have this in common.
Cargo Master
Joined: Oct 2012
Posts: 2,333
Likes: 35
From: South Carolina
There is a schematic in post 4 of this thread.
https://www.ford-trucks.com/forums/1...esof-inop.html
The schematic is supposed to be for 02-03 and maybe a few more years when Ford used multiple modules to control subsystems. I thought in 99 it was all lumped into one - the one under the engine compartment fuse box, if I recall correctly. Not sure how much is the same and how much is changed vs the schematic.
It shows relay COIL ground is on pin 85, and it grounded through the module. 87A is the CONTACT ground.
https://www.ford-trucks.com/forums/1...esof-inop.html
The schematic is supposed to be for 02-03 and maybe a few more years when Ford used multiple modules to control subsystems. I thought in 99 it was all lumped into one - the one under the engine compartment fuse box, if I recall correctly. Not sure how much is the same and how much is changed vs the schematic.
It shows relay COIL ground is on pin 85, and it grounded through the module. 87A is the CONTACT ground.
Cargo Master
Joined: Oct 2012
Posts: 2,333
Likes: 35
From: South Carolina
I have read of water getting in the module from windshield or other leaks.
Run a continuity check on the relay coil ground wires from the relay to the module to eliminate a wiring problem on that leg.
Run a continuity check on the relay coil ground wires from the relay to the module to eliminate a wiring problem on that leg.
Cargo Master
Joined: Oct 2012
Posts: 2,333
Likes: 35
From: South Carolina
I would start here:
Tousley Ford Parts Depot
Although maybe a junkyard might not be a bad place either.
Tousley Ford Parts Depot
Although maybe a junkyard might not be a bad place either.
Senior User
Joined: Dec 2011
Posts: 484
Likes: 0
From: Rockland Ontario
jsavin, like SC says, some need the software taken out of the module,
and uploaded back in the new one. But not all.
The supplier should say if it need's re-programing.
I know before I replace mine, I'll have the codes read, if any...
Many have replaced GEM modules just to find, that wasn't the problem,
whatever you decide, good luck and let us know if the issue is resolved.
and uploaded back in the new one. But not all.
The supplier should say if it need's re-programing.
I know before I replace mine, I'll have the codes read, if any...
Many have replaced GEM modules just to find, that wasn't the problem,
whatever you decide, good luck and let us know if the issue is resolved.
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Senior User
Joined: Dec 2011
Posts: 484
Likes: 0
From: Rockland Ontario
There is a schematic in post 4 of this thread.
https://www.ford-trucks.com/forums/1...esof-inop.html
The schematic is supposed to be for 02-03 and maybe a few more years when Ford used multiple modules to control subsystems. I thought in 99 it was all lumped into one - the one under the engine compartment fuse box, if I recall correctly. Not sure how much is the same and how much is changed vs the schematic.
It shows relay COIL ground is on pin 85, and it grounded through the module. 87A is the CONTACT ground.
https://www.ford-trucks.com/forums/1...esof-inop.html
The schematic is supposed to be for 02-03 and maybe a few more years when Ford used multiple modules to control subsystems. I thought in 99 it was all lumped into one - the one under the engine compartment fuse box, if I recall correctly. Not sure how much is the same and how much is changed vs the schematic.
It shows relay COIL ground is on pin 85, and it grounded through the module. 87A is the CONTACT ground.
Cargo Master
Joined: Oct 2012
Posts: 2,333
Likes: 35
From: South Carolina
Take a look - power to the coil comes in on pin 86 (fed from fuse 59) and the other side of the coil is connected to pin 85. That goes to the module. The module switches this from disconnected (coil de-energized) to grounded (coil energized).
Cargo Master
Joined: Oct 2012
Posts: 2,333
Likes: 35
From: South Carolina
Try module. Gem is an acronym for General Electronics Module. Maybe Generic. Anyhow, try using module and then look down the list.
Senior User
Joined: Dec 2011
Posts: 484
Likes: 0
From: Rockland Ontario
That may not be the point of ground, as it's not indicated as a ground point,
just sayin. Wouldn't want to unknowingly damage an chip inside.
Thats just me...lol
My next step, when weather permits, will be to check all grounds and power
to the module's, open up the module and check for corrosion etc.
I'll also see what makes it 'tick" what type of "chips" are inside and can they be replaced individually.
After that, I'll have the codes read. CTC over here will read them for 45$.
JS, here's a few on ebay to give you an idea.
GEM module 1999 Ford Expedition Lincoln Navigator 4X4 XL1414B205 XL1Z14B205AA | eBay
Fleet Owner
Joined: Apr 2012
Posts: 27,307
Likes: 549
From: Spanaway
Here is a tool you may find handy in tracking this down
Lisle 56810 - Relay Test Jumper Kit
Lisle 56810 Relay Test Jumper Kit | eBay
If you have a local auto parts store that has a good line of Lisle tools you
should be able to get just the one jumper that you need and save some $$
Sean
Lisle 56810 - Relay Test Jumper Kit
Lisle 56810 Relay Test Jumper Kit | eBay
If you have a local auto parts store that has a good line of Lisle tools you
should be able to get just the one jumper that you need and save some $$
Sean