4x4 Electronic Shift Control Module - '93
 

My electronic 4x4 not working. Auto-locking hubs and electronic transfer case. I found the Electronic Shift Control Module. There's an LED on it with a reset button on it. The light was initially off when I got to the box. There is a "reset" button on it, and the light will come on for a bit, then turn off. My first question is "what's the LED for"? It has no bearing on any power getting from the input side of the board to the output side. I'm wondering if it's some kind of indicator whether the board is good or bad.

I'm getting proper power to the board, as I have power to the wires at the ESCM from the switch when I press the 4x4 button.

However, outbound (from the ESCM to the transfer case)...here's my other question: The wiring diagram indicates two wires going to "Transfer Case Motor" (Yellow 777, Orange 778). When I press the 4x4 button, I get power to the orange wire leaving the module, but no matter what I do, I don't get power from the yellow.

Does anybody know under what circumstances I should have power at the yellow wire?

I hate to order a new ESCM without being sure this is the problem. It's a $500 part.

Thanks,

Rick

Check a December 24th post by shipwreck17 about the same issues. There is a wealth of information there on this subject. Have you verified that it is OUT of 4wd? Seems to be a real issue with Electronic shift. Also a module from another Ford was purchased from ebay on this thread from shipwreck for a very low price, correcting the issue. Good luck.
Tex

Here's an excerpt from technical manual:

Control Module Self-Test

The electronic control module has a diagnostic capability of its own circuitry. The self-test procedure is as follows:

1. Remove the five-wire connector and the eight-wire connector from the bottom of the electronic control module.

2. Turn the ignition switch to the RUN position.

3. Activate the self-test switch located on the module and note the result: a flashing indicator lamp (approximately one flash per second) indicates that the control module is functioning properly. A steady indicator lamp indicates that the control module is inoperative and must be replaced.

Check this out...after speaking to a local 4x4 shop near me, they advised me to put 12v to the t-case motor and see if I could get the motor to engage the transfer case, and determine if it's the control module, or the motor.

I had to cut the orange and yellow wires to get 12 to them with the connectors hooked up. I could hear the motor clicking, but not doing anything.

What was my solution?? Remembering the solution to stuck ford starter solenoids prompted me to whack it with a hammer. So, I got out a hammer and hit the damn motor, and it started engaging and disengaging when I put the 12 to it !!

So, when I had NO 4x4 before, now my 4HI engages and disengages as it should, but 4Lo will engage but not disengage unless I crawl under and put the 12v directly to the wire - that's no biggie, as I don't need 4LO.

so, where a module would have been $500, and a t case motor would be about $300 - it all boiled down to a hammer - lol.

I will replace that motor when I get around to it - but no rush now.

Thanks for all the input and advice along the way.

Rick

rpxr400,

have you damaged the 4X4 elec motor, if the hammer didn't do much damage I have a solution for your problem I think. This site has alot of problem solvers so wait before you start taking a hammer to your truck. I had a problem with my 4X4 push button system about 9 months ago, I got some info from a page that I will post to you when I find it again, did the repairs//took the motor apart, cleaned the brushes greased it up again put it back together and it has worked perfectly since.

phonebooth - I didn't damage the motor. It was evidently stuck, and the vibrations or shock from the hammer freed it up. prior to me hitting it, the motor was frozen - now it engages and disengages.

i'd be interested in seeing the link you mention about taking it apart and cleaning it.

Thanks,

Rick