4wd System Operation & Help Thread

having voltage available is not enough for these to function. It could also be a bum 4wd switch, bad wiring, bad ground connection, degraded limit switch, stripped gears, corroded connections inside etc. the failure modes are endless and all very probable given the quality of the parts design and history of their issues.

 

What I do know is t-case and diff actuators are good, ecu is good, I believe the switch is good too being that it will make the 4hi flash but no lights on when 2wd, t-case does actuate but the front diff does not, idk if that narrows it down but that is all I know as of now. My multimeter should come in soon and I can get my readings from the limit switches

 

i would challenge you with why you know they are good, have you bench tested them? Not saying they are not, but I wouldn’t disprove anything until you can test for yourself. Trust but verify.

 

Fully understandable, yes I bench tested them both, And swapped both with known goods off a truck that has working 4x4 and was left with the same issue, also while off the truck I inspected the internals on the ones off my truck, no corrosion and no stripped gears, and actuated when given 12v

 

Oh man I would love to have a manual shift and manual hubs.

 

if the subcomponents are all good that leads me to believe a poor ground or a bad connection somewhere.

 

the manual shift is very nice. Manual hubs are not available for this generation unfortunately. Full time hubs are an even better option in my opinion. My dad had a 97 pathfinder who never had a problem with the 4wd system and I always wondered how that was possible because that shitbox rusted from the inside out. When I checked I realized it had a mechanical shifting transfer case lever and full time hubs, simple is simply better in this case.

 

I finally found an answer I think. On the actuator piggy tail, when switched to 4hi and light blinking, 2 wires read around 17V, solid red wire and black/white(yellow maybe). No idea what those run to but that seems very excessive. The other wires are at .5v and 11.8

 

Those are for the motor, not sure how you'd get 17V unless your alternator VR is going out. What was your battery voltage at the time?

 

Battery is sitting at a clean 12.8, same as alt as I had that worry

 

That's strange, I would unplug the actuator plug and check continuity across pins 1 and 2 to verify motor integrity.

 

I checked at the ecu and had 12v at the highest and lows of .5 as well. Plugged it back in and now 4hi 4 low are flashing smh lol I can’t win!

 

Everything should be plugged in when checking at the 4WD ECU.

 

I definitely biffed that then, 100% checked when unplugged

 

I may have gave him some bum info, but I do like to check the motor continuity right at the actuator. I'm not sure what's driving the other end of that motor like a transistor or a relay? So I like to get motor resistance right at the actuator without the impedance of the ECM affecting the readings.

 

Yeah, your information was good.
I just want sure if he was doing any of the voltage checks with anything unplugged.
I’m still trying to figure out how there was a reading of 17v?

 

I have checked voltage everywhere with the plugs unplugged, I did just order a set of t-pins so I can do it right. I really didn’t expect that to make a difference plugged in or not

 

I got a box of T-pins at wal-mart.
They are in the sowing isle.

Sharp as wiz, so be careful.

 

It would help to know what voltages you are getting on what wire (pin) and under what conditions, just saying you got 0.5-12v doesn't really help narrow things down. The 17v is kinda curious but I would ask where your meter ground was connected to, ideally you would want it connected to battery negative but frame or body ground would work too.
If checking the limit switch voltages you would want everything plugged in as a baseline then once it's narrowed down the the suspect circuit(s) you may need to unplug things to verify circuit integrity.
With the actuators unplugged all the limit switch voltages should be at 12v if the ECU is good and there are no shorts to ground in the wiring between the ECU and the actuators.

 

You figure it out quiet well!. Check this out.