Hi Bluegrass 7
First off I wanna thank you for taking the time to reply. After reading your previous replies to other members, it was clear that you were quite knowledgeable in this field and especially with these particular vehicles/issues. It's for that reason that I decided to ask your advice on the issues I'm having with my 2002 f-150, and if it's all the same to you, I'd like to give you an update on a couple things I done today and inquire further in my pending issues.

Today I took transfercase motor off and manually switched transfercase into 4h. The dashlight 4x4 indicator came on informing
me that the truck had switched into 4h. I put the trans case motor back on and tried to use the selector switch to see if it would work but it still done the same thing as before with the clicking when engaged but wouldn't disengage 4x4. Does this sound like an issue with the trans case motor for sure or perhaps something else? Could it be a faulty selector switch not sending signal to case motor to engage? And is there any way that I could check the trans case motor to see if it is flawed or check the wiring coming to the trans case motor perhaps to see if it has proper signal coming from selector switch to engage it?

Again, thank you for your previous reply and I will be extremely grateful if you find the time to reply once more

 

Plug the case motor back up and hang it in some way so you can see it.
Operate the Dash switch.
It should rotate one position.
Return dash switch to off, it should reverse.
If not, either the motor is faulty or there is no power getting to the motor.
A voltmeter test can be done to check for power.
Good luck.

 

Thanks Bluegrass 7. I'll try that today. I suppose the fact that the 4x4 light came on when I manually engaged 4x4 on transfer case, rules out the possibility that the circuit board could have issue sending ground to fender wall relay as you mentioned earlier, right? By the way, where exactly is this circuit board located that you're referring to? And also I was wondering if it might possibly be the transfer case switch (or sometimes called light switch) which has the bearing in the end that might be causing my issues?

Thanks for all your advice and Intel, Mark

 

Good Morning Mark. I have been following this tread for an update. Did you ever figure out your 4x4 issues. I am having the same issues as you have described.

 

PM sent to Bluegrass 7, interesting thread. Thanks for all the info to everyone.

 

I see some very good information in your posts Bluegrass 7. I have a 2003 that will not shift into 4WD. It has been sitting all winter and I just got it back on the road last week. However, when I tried engaging the ESOF, I am getting no signs of it working. No dash light, the switch ohm tests okay, I have power to the solenoids and TC relay but nothing to the TC shift motor. It also appears that I am not getting any signals from the GEM to the solenoids or TC relay which does not seem to be activating the TC motor circuit. Everything seems to point to the GEM so I scanned it with my inexpensive wifi scanner and found two B codes and several P codes relating to open circuits on the solenoids, TC relay and many on the TC motor and plate. I removed the GEM to see if there were any signs of moisture damage and found none. so I have reinstalled it and cleared the codes to keep it drive-able for now. I did re-scan the GEM and only got two P codes relating to the shift plate in the TC motor.

I found this thread after researching the latest codes and want to be sure that it is the GEM that needs replacing before purchasing. I have read a few forums about the TC motor being a likely culprit but it seems that most people just start spending money on one part after another hoping to solve the problem. Your posts have been the only ones that have actually run through the sequence of the 4WD shifting process. Before I look at replacing the GEM, is there anything I am missing? If the TC motor is seized and not activating, will that automatically stop the GEM from sending signals? Without putting the vehicle on a high end scanner that will control the GEM PID's, is there any way of narrowing this down further?

Thanks in advance.

 

Just to be sure, the Case motor is powered through a relay in the dash from a separate fused source,
Do you hear the relay operate? If yes, is the supply fuse to the motor missing? If no, the Gem is not addressing the relay operation for some reason.
A further test is to look for voltage at the case motor plug. Often if the case motor does not run, you may hear the relay click multiple times trying to connect to the motor.
If not sure about any of this, remove the case motor, then with plug in place operate the dash switch and see if it moves.
The Dash lights depend on the motor rotation because there is a circuit board and wiper contacts that close the circuit to operates the firewall solenoids and reports back to the GEM where in, the Gem lights the dash lamps per the function requested.

 

There is power to the relay but it does not click. There is no power at the plug for the TC motor. If I am not mistaken, there is one fuse (23) at the junction box that feeds the solenoids and one fuse (104) in the power distribution box that feeds the TC relay and motor. Both of those fuses are good.

Am I understanding the electrical sequence correctly? Switch > GEM > TC Relay > TC Motor > GEM > Solenoids and Dash Lights. Given the switch is getting power and it seems to have the proper resistance in all three positions, my thoughts are it is either the GEM or the relay. How do I test the signals from the Switch > GEM and GEM > TC relay?

 

Did you ever get this resolved? I am having the exact same issue on my truck.. no clicking.. I
I've replaced the GEM, both solenoids, the 4x4 switch, fuses are good.. but nothing not even a attempt to click from the relays when I switch in 4x4.