XJ Wizard Needed

[derf]

4 hours ago, AZJeff said:

Yeah, I realize that, and that’s why these intermittent issues are bugging me, since I checked continuity of ALL. Circuits except the CCD bus.

Wiggle the wire around while you're testing it.  It could be that holding it in one position will keep it appearing to be in good shape when there is some issue with it when it's bouncing around in a moving vehicle.  And do all of the other testing for crossed wires, shorts to ground, shorts to voltage etc suggested above.

[Warren Mohler]

16 hours ago, AZJeff said:

16 hours ago, Warren Mohler said:

 

I assume the DRB3 is a dealer diagnostic tool.  What do you think the odds are of a Jeep dealer having this tool as it applies to anXJ

Any Chrysler, Dodge, Jeep dealer should still have one if not something better, plugs into OBD port, hopefully you have one, with proper cartridge it should support all models, the beauty part is you can select system, cruise, antilock, passive restraint, trans, hvac etc. and then monitor inputs outputs to possibly isolate problem, it is best scan tool I ever used. Being you have MJ with newer equipment I'm sure any tech would like to help maybe during lunch as it should not take too long being problem seems to be constant

[AZJeff]

On 12/17/2019 at 6:03 PM, Ωhm said:

 

Continuity testing will only find OPEN circuits. Each wire also needs testing for Shorts to Ground (STG) and Shorts to Voltage (STV). KEY OFF, select Ohms for STG. KEY ON, select Volts for STV. Doing these tests on the CCD bus, if its twisted paired wires will prove out the wiring, not the communications though. Also WIGGLE all wires when testing.

Good points.  I have not checked to see if there are any intermittent shorts to either ground or power on the lines I have tested.  I will do that.

 

[AZJeff]

On 12/17/2019 at 6:18 PM, Warren Mohler said:

they should never run parallel to add on circuits and only cross others at 90 degrees also they were very light wires not much more than telephone wires

I am familiar with twisted pair wires and how they are supposed to function.  Given they are not supposed to be in close contact with other circuits, I would assume they would be in their own separate harness, and not part of any other wire loom(s).  I will look to see if that is the case in the stuff on the back of the instrument cluster wiring.