4WD InOp Condition: ECU or Position switch?

Hey guys,

Figured I'd start a new thread on this problem.
I recently went back to do a small amount of troubleshooting.

Problem: 4WD Not engaging, neither will the electronic rear diff. lock work

Truck is an 02', 3.4L, 5-Speed manual, J-Shift 4WD TC, Truck has electronic rear diff. lock button option.

Transfer case is working properly and engaging/disengaging the front drive shaft to the front diff.
Front diff. actuator is not engaging to lock the hubs.

I removed the 6-pin connector to the front actuator and tested continuity on the pins for 2WD and 4WD options.
It appears continuity is not present when selecting 4WD inside the cabin, only 2WD pins have continuity.

Since I'm not getting any relay clicking inside the cab when selecting 4WD, could this mean either the position switch on the transmission or the 4WD ECU is suspect?

I removed the 4WD relay on the passenger-side floor board and inspected it, but didn't see any noticeable damage.

Any suggestions for the next test?
Is there a simple test to rule out the position switch on the transmission? (I'll try to look that one up.)

 

Crawling under my truck, on the driver’s side and passengers side, I find sensors with 2 wires each. I was not able to get any continuity on either when changing from 2wd to 4wd with the j-shift. Should I have been able to? Or am I missing the location of the position switch sensor?

 

If j-shift, you don't have an 4wd ecu. Just the 4wd relay. As far as the relay is concerned the 4lo switch is a ground continuity NO switch. The 4HI switch is a NO vlt feed to a terminal of the relay fed from the 20A 4wd fuse. Since the elocker ECU and the 4wd relay need the 20a 4wd fuse, I'd check that first. Put a new one in, just for S&G.

Easy test for the position switches is a continuity test. Pull the connector. Put each probe on each terminal of the sensor. Test first in 2wd, you shouldn't see continuity. Test 4hi first by putting the shifter in 4hi, you should see continuity here. Repeat with the 4lo switch.

There's a testing procedure for the relay and the actuator in the 03 Fsm floating around this site. I have a link to a copy in my Dropbox if you can't find it.

I'm totally pulling this out of my ass with no facts; but 99% of the time an ADD j-shift truck loses the ability to actuate the actuator is because of the actuator.

 

Oh and the position sensors are on the transfer case. Most likely blue connectors.
Driver's side is the 4lo switch. Pass. side is for 4hi. And I've read with an automatic transmission comes a third.

 

Where is the relay in the passenger side could someone post a picture of the location I can't find it in mine