Ok this is on my 97 F150 XLT 4x4 with the electronic shift on the fly.

Been having some issue with the car not engaging 4H. I will select 2H and 4L with no isseu.....anyways here my question.

If I put another TCM in but do not hook up the wire that goes into the transfercase, I guess this wire charges up the coil in the transfercase so it's up to speed when you select it while driving, will it still make the 4H selection?

Here is why I'm asking. Right now I can select 2H and 4L with no issue. For 4H all I get he relay clicking. Somehow from what I read there is signal at the TCM sends back to the GEM to activate the 4H.

When I put the new TCM in it did no have a wire for to connect to the wire coming out from the TC. I just left in unplugged and with the car in park tried the switch not luck. I ruled out the TCM since it did not more and took it back. I did have the right TCM, I just didn't remove the red bracket and insert the wire since a member on a other board said that wire was not required unless you are driving and engaging the 4x4 systam. I want to verify this before spending $88 for the dealer to tell me what's wrong.

Does the GEM need that wire as a signal even in park to activate 4H, or is it just to charge up the coil to bring the system up to speed when driving?

 

It should still shift into 4H while at rest if the ESOF clutch is not energized.
I can't see any feedback type wiring in the ESOF clutch circuit that would signal the GEM to not do the 4H shift if the clutch is not energized...but that's not to say that there is some internal circuit-watching going on inside the GEM.

The only thing I've found on the ESOF relay locations is that on the Super Dutys they're supposed to be mounted on the driver's side inner fender under the hood. I know there are relays clicking under the dash of my '97 F150 too when I shift so I still think they're under the dash some darn place. I suppose a call to the dealership might get you in touch with a tech that'll tell you the location too...unless they are just hell bent on getting you to bring in the truck so they can get a service charge out of ya.

BTW, I found the electrical and vacuum diagrams for the '97. Check your email, they're on the way.

 

I got the diagrams, thanks a lot.

As for calling the dealer...no luck I tried 2 different ones here and they both say I need to bring the truck in. They gave me the same thing about the window issue I had a while back.

They want $88 to hook up the truck to tell me what's wrong with it. It would really suck to give them $88 to tell me it's a relay.