HI, I’m new here. I’ve looked around the forum a bit trying to fix my 4 wheel drive on my 1997, Ford F-150 Lariat with a Borg Warner 4406 (not certain what # id’s the transfer case). I’ve owned the truck since new.
Here’s the issue: A few years ago the 4 wheel drive would get slow to go into 4H and 4L. One day, it failed altogether, just a lot of clicking in the dash. 30 minutes later I tried again, it went into 4L and would not come out, no lights, no nothing. I drove it 1 mile back home, and the next day, tried and it went back out into 2H. I got busy and just didn’t use it. Now I have time.
Sometimes, when you select 4WD, you hear a clicking sound up in the dash, I assume that’s the Transfer Case Shift module, sometimes it’s just a single click and the 4H comes on via the dash light, sometimes, it clicks over and over and the dash light comes on, sometimes as in the other day, it clicks and clicks then nothing happens and the 4WD switch no longer acts like it’s working and no lights.
2 days ago I pulled the motor and tested it’s rotation with a 12 volt battery and its strength by holding a screw driver in the slot while it was moving. Today I using a wiring diagram, I check the switches on the transfer case motor. The diagram is drawn with all 4 contacts open, so I don’t know what’s right. But here’s what I got: with Yel/Wht as common and the motor CW (as facing the triangle socket) I got continuity on all except the Brn/Wht. CCW: continuity on all but Prl/Yel. With the motor in the center position, I only got continuity on the Prl/Yel.
Being that the transfer case was again stuck in 4L, I took some pliers and rotated the shaft to the 2H position as marked on the transfer case, it rotated very easy. I then put the motor back in this morning and all is working again. I hate intermittent problems! I had hoped the motor was simple bad.
I’m hoping to get a target to go after.
So is it a:
bad connection
bad motor/position switch
bad shift relay
bad gem module
bad dash switch

 

After reading about your efforts to find the intermittent, you getting lost in the weeds.
Stop at the function where you hear the relay clicking.
Nothing after that is important until you get the case motor to run without clicking the relays.
Look at the power supply fuse, harness and the power plug-up to the case motor.
Is the fuse seated good in the fuse panel? the harness good and the plug-up clean and free of fault?
you may check this with a voltmeter when the fault is present.
If the case motor does not rotate, no signal comes back to the GEM module from the circuit board to confirm it has moved. This causes the GEM to retry and is the repeated clicking you hear.
It has to work that way so the GEM can remove power from the case motor to stop it in each position. The reverse power polarity to run the case motor in reverse.
Basically the case motor is not being powered for some reason either direction at times..
It's an electronic system combined with a DC motor, relays and return signals.
Look at it from this point.
Your not interested in anything beyond this point because the rest of the action appears to work ok if it will go 4H and 4L and return to 2wd at other times..
Good luck.

 

Bluegrass, thanks for the reply. That clears up why the system sounds like a breaker clicking on and off. Wonder how many times the GEM sends the move signal to the motor before it quits and what does it take to reset it so it will try again?
I have had the fuses out several times and feel they are ok, but will thoroughly clean them tonight. I kind of suspect the plug at the motor and cleaned the male side before reinstalling (wish I had cleaned the female side as well).
I have another question. If the position switches on the motor are intermittent feeding information to the GEM, would that cause the same GEM cycling issue?

 

Yes if the circuit board contacts have a fault.
Yes there is a Timer on the operation to stop it from going on and doing un- necessary damage to the relay contacts for no reason.
The GEM can do a lot of things depending on the build of the vehicle and the options.
It does the wiper delay function, the power window control, the cab inside lighting and other timed functions and is programmable.
Good luck.

 

Thanks, that clears things up and is a relief. I feel the GEM is doing what it's suppose to and will keep looking at the plugs and switches. The location of the transfer case motor and plug are really in a nasty spot and my inclination is toward them or the shift relay in the dash, since it has pretty hi current flow and the contacts could be arc damaged. I find the motors easily, but not the transfer case shift relay module. Are these hard to find?

 

I'll try asking the above post in a different way. I've searched and searched and can't find the transfer case shift relay modules, for a 1997 Ford F150. Are these still made. Am I searching for the right name?