Hi all I have read the sticky on trouble shouting and still confused. I get no lights no nothing it worked fin in spring but haven't needed since. now time for plowing and nothing at all. ban anyone tell me what i should get at the selector switch for voltage I tried testing the 4 wires. the black and white is a ground, the i think it was gray have 12.6 volt and one blue had nothing but the blue one closest to black seems to be ground as well.

 

You need to know how the system works first before going into any meaningful testing or you don't know what is and isn't.
The switch signals a control module.
That module conducts the system operation through relays, a DC transfer case motor and a front axle actuator.
First you need to hear the case motor run to it's first position.
Of not, main power to it is not being supplied so that would be your first diagnosis.
If yes, is the front actuator being supplied Vacuum?
If no, the firewall solenoid is not operated or vacuum is missing.
What does or does not happen in this sequence is the key.
Go back and reads the help thread again and try to understand.
Wasting time trying to measure a switch condition is not the place to start first.
The learning curve is difficult if you don't take time to understand what your supposed to see happening in the system.
Trying to guide you on a board at a distance is also difficult because you have to convert guidance to actions..
Good luck.

 

Thank you For the reply I appreciate it very much. I have checked the solenoids on firewall by placing finger on them and having someone turn them on and off there is nothing. the transfer case motor does not run either. I will check these again this evening and confirm again thanks.

 

You need to go in order.. NOTHING happens on the firewall or front axle until the transfer case motor switches. You need to see if you have power to the motor, or pull the motor, set on the floor and toggle the dash ****.. If the motor runs and switches gears, THEN you get one light and THEN you need to check axle and vacuum.. Get the motor to run or verify that it has no power or "stuck".

 

If the transfer case motor does not move to it's first position the firewall solenoid will not operate.
Address the case motor operation first.
Check supply fuse #104 in the engine bay box.
Plug seating at the motor location on the rear of the transmission.
.
There are other fuses feeding the Gem module that should be checked.
See you manual for the assignments.
Good luck.

 

I didn't get time to test for power at case motor today but with any luck i will after sand blasting a plow in morning. thank you guys for setting me in right direction i will post my results as soon as i get some. I did check #23 fuse that was fine and #104 under hood was fine as well.

 

its not uncommon for the motor to get "stuck" and not move, or have a bad connection in the electric plug..... pulling the motor off for inspection is not a big job.

 

Hi all I finally have time for this project and have pulled the drive motor and tried testing for power there is no voltage at plug that i can find. fuse 23 is good the other out under hood is good I had ignition on and the selector set to 4H when i put fuse 23 back in i could hear a clicking under dash. i did check fuse box at 23 there was 12.46 volts. is there any way to bench test drive motor. and can anyone tell me what wire at plug for drive motor should have voltage. thanks for any help I really need it.

 

I am thinking it is most likely the GEM module at this point what you guys think i really cant just throw money at it so am praying for advise here.

 

I think you should read BLuegrass post again.......... and check fuses.

 

I have read and re read I also have pulled every fuse in the truck and checked them three times now inside cab and under hood. paying close attention to those that are said to be for GEM. Unless there are fuses else where I cannot see.

 

I an having the same problem with my 2002 lincoln navigator did you ever find the problem ?

 

Hi Nick - that Lincoln has a completely different 4-wheel drive system.
You want to go over to the Expy/Navi Forum at:


Expedition & Navigator - Ford Truck Enthusiasts Forums


and describe your symptoms. There are some knowledgeable guys over there on the Expy/Navi 4-wheel drive system

 

Post #8.
.
'"I hear clicking under the dash".
.
This tells me the Gem is operating the relay to run the case motor.
If the motor does not run, the relay will be cycled several times trying to get the motor to run then the GEM times out.
This tells me the case motor or circuit has an issue. It has no power to it, the case motor is faulty, the harness is open, the plug is faulty etc.
Until you get the motor run so it engages the transfer case, the front will never lock because it's at the end of the whole operation and still it needs the transfer case engaged to the front drive shaft and would have no drive to the front Carrier/axles..
For this to happen the case motor has to move one position and close the circuit to the firewall solenoid so it transfers Vacuum to the Actuator.
You have to understand the chain of events and not hop all over the place.
.
Additionally, it is even possible the case motor runs to first position and the front does not engage. It can be a stuck piston in the firewall solenoid not permitting vacuum to the Actuator.
In this case the 4x4 light will be on but the front is not engaged.
The solenoid is the inner most one for front Actuator engagement.
Take the top cap off and apply liquid Silicone spray and operate the system several times if there are no other faults.
Good luck.

 

No vacuum actuator on the 2002 Navi.