Ok I posted on here and a few of you said to test some thing before posting again so here is what i got and where I need input. This is on my 97 F150 XLT 4x4 with electronic shift.

My 4x4 High will no engage with selecting 4H with the electronic shifter. 2H and 4L will. I replaced the switch removed the TC motor to see if it actually is moving it. It does not. When you select 4H the relays clicks under the oval by the passenger side.

things I did:
-replaced the stock TC motor and it did the same so I took that back and put the stocker back on. I had the motor off the TC to see if it spins the rod that actually moves it in to the selected position.
-replaced the electronic switch, still doing the same thing.

-bench tested the switch to make sure it's not bad either. I get the specified ohm resistance reading for 2H,4H,4L as I was told to check.

-I moved the relays around under the oval to determine witch one is for the electronic shift, but they all made the clicking sound. It just clicks click clicks clicks when you select 4H. Light does not come on and the clicking just keeps going till you select out of 4H.


questions I have:
-Does the GEM see anything after the switch has it's selection made or does it go the Relay and then to the TC motor?
-how do I test he signal after it leaves the switch?
-hint on how I can check at the relay to see if the GEM is sending the right amount of voltage.
-what pins can I check on the wiring harnes on the TC motor to see if there is anything going to the TC motor. I would assume no voltage since it's not moving when a selection is made.
-it was mentioned there was a relay behind the dash, guidance on how to get to it the easiest would be appreciated too.


thanks for any help. I'm really hoping to get this fixed this week since the snow is coming.

Thanks,<!-- google_ad_section_end --><!-- / message -->

 

tonight I looked at the vacum lines and noticed something strange and this might be my cause. There are 2 vacum hoses going from the front end light blue and red or orange that go behind the battery. There is also a black rubber hose (larger) that is plugged into the front end that runs along the vacum hoses....does that black hose lead to somewhere or is that just a breather hose? I was looking at it and it seemed to be cut, again that is if it's not a breather hose. Just seemed odd.

 

Now I dont have the Dash type 4x4 switch,,,But I recall where the TC motor has to turn,,,clockwise,,and counter clockwise, to do the engaging and di-engaging from 2H to 4H to 4L and back,,, By what your saying the TC motor,,seems to be turning in both directions,,,But skipping the 4H engagement,,If it goes into 4L,,and back to 2H,,it sounds like a 4H relay or switch or connection,,,That GEM module is suspect to me. Good Luck !

Thats why I like the Manual 4x4 system.

 

The larger black hose is a line to the vacuum reservoir that is inside the fender. If any of those lines are damaged, then it could be your problem. The blue and pink lines go to the vacuum relays that operate the front axle vacuum motor. Damage to these lines is caused from corrosion from the battery that is right there. You might also want to take a look at this thread as well. https://www.ford-trucks.com/forums/7...ml#post6813704
Good luck!

 

The larger hose, someone mentioned it was a breather hose just like the rear end has.

Do you by chance have a diagram or picture of where teh black hose is suppose to go. Like I said on my truck that hose it taped together with the pink and blue hoses all the way up to where they meet the plastic connector that leads to the battery area. the hoses were tied together. To me it looked like the hose was cut or corroded, but I didn't find a spot where it needed to connect to anything. Now I have 2 seperate answers from 2 different folks. Where in the fender area does that hose need to attach too?

I doubt that is causing my issues....I'm starting to lean towards the GEM myself....I'm hoping not, but no one seems to have seen this issue before and I'm stuck. I really dont want to pay te dealership to run a diagnostics just to tell me what needs to be replaced/fixed.

the switch is good...I bench tested it. the specified ohm readings are displayed when making the selections. On the TC motor, it does go clock/counter clockwise but skips 4H.

Thanks again for the input.

 

The vacuum resevervoir is behind the inner and outer fenders. It is a long molded black plastic tank. You're right, the larger hose wrapped with the blue and pink lines to the relays is a vent hose for the front axle. I wanted to make you aware that corrosion from the battery has been known to damage vacuum lines in this area.

Did you look at the other thread that I refferenced? Good information there.

Good luck!

 

so I can let the black hose be then since it's only to vent correct. I have not looked at the link...sorry...I got so involved with typing I forgot you posted a link. I'll check it out now though.

Thanks,