This is related to my original post about my electronic 4x4 not working. 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 from the switch when I press the 4x4 button.

However, outbound (rfom 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 box, 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

 

Have you check continuity on the moter. I see you have checked voltage. also do you have a clip on ampmeter cause you may want to see what kind of amps you pull when trying to engage the 4X4. It may not be a board problem it could be the moters toast, pulling high amps, and engaging some sort of limit switch (like that LED/Reset Switch). If this is the case then look for a new part. Better yet look for a used part from a Junkyard or used auto parts store. If you wanna know how to check this stuff to see if its mechanically sound then let me know.

 

The yellow and orange wires are a polarity reversing operation. The POS should swap wires each time you press the 4WD button. The first time should engage, the second should disengage. If its not doing this, then either the shift motor is seized/stalled and the shift module is interrupting the power so as not to fry anthing or somethng in the module isn't allowing power out to the yellow wire. Keep in mind too that there are four positioning sensors that will also keep the power from flowing if they do not detect the proper alignment of the shift motor when the button is pressed. Often what happens in these situations is the motor gets stuck between one position and another and since the sensors can't establish a position, they don't allow the power through. Sometimes manually moving the motor to one position or another will get the system going again but if the motor hung up in mid travel once, it has the potential to do it again.

 

Processor board (passenger side kick panel) has a 2 wire harness attached to it . Remove this harness and now u can push the white square button (bottom edge of the processor) and it will turn on a red LED light. Red light flashes this means u have a problem with your actuator motor ( transfer case shift motor ), if the red light stays on (bright) this means u have a problem with this processor. Like Greystreak stated its usually the shift motor hung up between positions and not the processor board . Trouble with my shift motor revealed the ruber tube like stop completely disenagrating throwing the shift motor out of position to know electrically where it was at.TR

 

Check this out...after spaeking to a local 4x4 shop near me, they advised me to put 12v to the 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?? Knowledge from fords in years past had me remember the starter soleniods - how they stick. I got out a hammer and hit the damn motor, and it started engaging and disengaging when I out 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