@soundquest ;My 4-LO has been inop. for some time now with various lights illuminated (ESP, BAS, TracCont.). The FDCM has the most recent software update referred to by Chrysler as P73. Attempts at resetting the FDCM (fuse-pull trick) have failed. Well I went in to take a look at the wiring harness and wiring in the pass-through section of the backseat (underneath the access panel that allows you to see the FDCM) and viola! I found two broken and corroded wires. One is brown (skinny gauge) and the other is red (larger gauge - not sure if it has a color stripe as well on the red wire). I know the transfer case motor has a brown wire coming right off of it -- my plan is to continuity test from the motor side of the wire, and the broken wire side under the backseat. But access is TIGHT and I cannot even get inside the passthrough hole to strip it and test-probe it. I will either need to remove the large plastic piece (that the FDCM sits on and the other module in the picture). Does anyone know how that piece pulls out? Also -- would I have better access from the underside instead perhaps? I know that big plastic shield on the underside would need to be removed. I am guessing that restoring both wires with some good donor wire and solder/heatshrink tubes and that FDCM will be back in business and in communication with the main computer... allowing my 4-Lo to work again and making all the annoying lights go out (then I can use cruise control also). Anyhow -- really just wanting to know a few things:
1. What circuit is that red wire a part of?
2. How do I remove the plastic platform piece in question (allowing me better access to those wires)?
3. Would access and splicing be easier from the underside?
4. In one of the photos, you can see how the tape has become frayed and compromised and another wire jacket is starting to come apart -- has anyone else had this issue and if so, what is the solution besides just wrapping it with more tape (after making sure there are no other wire breaks). Thanks.
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Welcome to the forum;
That is almost certainly the wires running from the FDCM to one of the actuator motors on your transfer case, or, maybe to both of them:
There are actually 2 actuator motors for the transfer case, in case you were not aware.
An upper actuator motor & a lower actuator motor, which are mounted on the transfer case housing & I've been told, the lower actuator motor is the one that is easily accessible, the upper actuator motor is supposed to be much tougher to get to.
Those broken wires definitely explain why you lost the ability to shift down into 4-LOW;
I had one of the actuator motors on my transfer case replaced (the lower transfer case actuator motor) but, I had it done at the dealership a number of years ago; Shortly after that, the P73 campaign notice came out;
I sent my repair bill to FCA and they fully reimbursed me for having the transfer case actuator motor replaced; But the point being, I didn't do the work myself.
A couple of good threads about it here;
Chrysler/ Jeep P73 Campaign. | Page 2 | Jeep Commander Forum
4WD System Service Light | Page 11 | Jeep Commander Forum
The only thing I can recommend is to try & locate the "lower" actuator motor, on your transfer case housing & see what color wires are going to it.
That might help answer some of your questions.