When you push the white button on the shift module dose the red led light up? And does it flash or does it stay on for aprox. 10 seconds.

I am not aware of any clutch in the shift motor.
I have a 87 bII and the motor in mine runs from 2 high to 4 high to 4 low. then back. the power to the motor is supplied to the moter untill the limit tells the shift module its in the position selected. If the module dosent know what position the motor or trans. case is in it wont even try to shift.

You can take the module apart and run the moter by the relays but all this will tell you is the motor power wires are good.

To change to man. shift I think you would have to change the trans. case.

 

when i push the reset button, the red light does not come on, the old module was the same. what does this tell me????

What kind of screw driver do i need to take the cover off above the limits, they look like torx, but there is a pin in the middle preventing the use of the screw driver?????

thanks for your input.

 

It sounds like you have a reference manual of some kind, so I don't know whether it's necessary to explain how to run the Self-test on the Transfer-case Electronic Control Module. The light should blink about once per second for a "Pass" condition. Anything else indicates a failure.

The '88 Bronco-II I got for use as a parts doner to fix the major problems on my '84, had a lot of irreparable weather related damage. It electronic transfer case was working in fits, and I guess that's why I kept the 5-speed and manual case originally built into the '84.

One peculiar thing I discovered during the time I had the '88 was the inner plastic fender "splash" shield on it had somehow gotten pushed up to where its lower-back edge was caught and pressing down on the flex-conduit-wrapped wiring harness against the hole in the frame through where it is routed.

I don't know how it got in that position, maybe a build-up of snow inside the fender which was pressed up on by the front wheel being turned left while moving forward. Nor can I say exactly how long it had been that way, but it was apparent it had been in that position for quite a while, as the flex-conduit was completely cut through and the insulation on a few wires was perforated and making contact with the edge of the hole. There was ONE wire, who's conductor strands were completely severed. After checking, it turns out the cut wire, wasn't for anything critical; one of the dash "4x4" indicators.

The wiring for controlling the electric shift-motors runs under the carpet along side the center bulge in the floor, next to the driver's seat, then goes through a grommet in the floor. There are multi-pin connectors directly on top of that tunnel just under the dash, for that harness. The rest of the wiring goes behind the dash panel over to the electronic control module, as well as behind the instrument cluster and through the left windshield pillar on its way to the Overhead Console. On the '88, all of that wiring was in great shape.

I don't know what, if any of the wiring going down the left frame rail is pertinent to the "4x4" control electronics, so looking in that direction may not help your situation. However, there are "P"ark and "N"eutral sensors which are checked for a "True" status condition prior to activating the shift motors. Wiring to/from those switches on an automatic transmission usually runs down along the top of the transmission. That wiring and.or its insulation could become damaged from heat and friction over time, and the switches can become more intermittent in their reliability as they are used.

Manuals describe replacing those switches as a fairly delicate procedure, possibly requiring special tool(s), so I suggest considering all your options before jumping into swapping them out.

Here's what the Ford Factory Service Manual says about the operation of the Electronic Shift Control System:

"In operation, when either of the two switches in the Overhead Roof Console are depressed, the Electronic Control Module will analyze information from the transfer case Shift Position Sensor to verify its current position. It will also analyze input information from the Speed Sensor (inside the case) and the Clutch Interlock Switch (manual transmission) ...or Neutral Safety Switch (automatic transmission) .... If all the design conditions of the system are met, the Electronic Control Module will command the Electric Shift Motor to execute the desired function. After the shift takes place and the motor is turned off, the Electronic Control Module will again look at the inputs from the Shift Position Sensor to determine if the transfer case is in the position that the operator selected. Finally, the Electronic Control Module will illuminate the pushbuttons in the Overhead Roof Console to indicate that the desired function has been completed."

I hope this helps you!

 

Thanks that is all good information. So now i know where to start to trace wires.
Iam hoping its some thing like a corroded wire some where in the system.
My book doesnt mention anything about the white self test red light feature. and on both control modules i got no red light flash.
couold both modules be defective, or could a faulty ground wire be resposible. ?????
Well iam off to tracing wires, love the old manual system, much easier to diagnose.
i love a challenge,. i may have to go and buy a new shift motor. to be sure that thats not the problem. the motor appears to work but if the location, sensors are not working right, then perhaps...a new shift motor would fix the problem.????
thnaks again for oyur information it helps a lot.

 

If one thinks in the following terms; solid-state electronics never wears out, while mechanical apparatus always wears out, during NORMAL use, I'd be inclined to look in the area of the shifter motor and the (mechanical) Position Sensor Switches (PSS).

The motor and "PSS" module are integrated together. I don't know how serviceable either of two aspects of the assembly are, but since the problem is most likely with that part, you're not going to lose much by trying to repair it.

Connections OUTSIDE the vehicle and exposed to "the elements" are also possibilities. Use isopropyl alcohol for cleaning contact in those wiring-harness connectors. After cleaning, use a lithium grease to coat the "O"-ring seal area along with a small amount inside with the contacts, to keep the potentially corrosive 'elements' out.

The "electro-motive" cleaners, available at many auto parts stores are okay for the motor-PSS assembly, but the solvents in them will "melt" the plastic housings of wiring connectors.

As always, I hope this has helped!