4x4 Electrical Problems

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volunteerff21

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So my 4x4 has been broken for quite some time now. With winter approaching soon I'd like to have it working.

Truck is a 96' K2500 with the NP243 T-Case.

On the dash button the 2-HI button is always lit. So the TCCM (Transfer Case Control Module) knows it's in 2-HI. When I push the button for 4-HI the button will just blink. When I push 4-LO nothing happens, no lights, no blinking, nothing.

The front actuator does not move at all. I tried replacing it but no luck. I checked with a voltmeter and it's not getting power. As far as I can tell the transfer case isn't engaging either. I can spin the front driveshaft easily by hand. I also tried replacing the transfer case actuator (the thing that screws into the top of the T-Case). Again no luck.

I've had the truck to two shops so far. One shop couldn't figure it out. The other suspected a bad TCCM. Replaced it and it didn't fix it.

I jumpered pin 13 on the OBDII port and pulled DTC #1. Now this is a quote straight from the service manual for DTC #1 "When the ignition switch is positioned to RUN the TCCM test to determine if RAM standby power (maintained battery power) to the TCCM was lost since the ignition was last turned off. When power is interrupted to pin C6 on the TCCM, the TCCM stores a loss of RAM standby power."

So I pull the plug to the TCCM and start poking around. Now here's the pinout for the TCCM connector.

http://s1349.photobucket.com/user/volunteerff21/media/Pushbutton4X4-025_zps9e85ce4f.jpg.html

I am getting power at pins C9, C11, D2, D3, and D15. I'm fairly certain I should be getting power at pins C2, C6, C8, and D14. And I shouldn't be getting power at pin C9, because that's a ground.

Now I've already done the usual fuse checks, everything looks good there. Truck also has brand new ground straps.

So what are ya'll's thoughts??

P.S. A big thank you to Great White for all his help already. And thanks in advance to anyone who can help.
 

CaRaZy

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As someone pushes the 4x4 hi button do you hear the force motor doing anything on the tcase?
 

volunteerff21

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The force motor does sound like its engaging. And this time when I turned the front driveshaft after my helper pushed the button I could only turn the driveshaft maybe an eighth of a turn. So does this mean my transfer case is engaging????
 

glfirefighter144

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Possibly, have you followed all wires from the front actuator. Don't know if the push button 4x4 has one, but my floor shift 241 had a switch on top of the transfer case that sent power to the actuator when engaged that went bad and I replaced

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volunteerff21

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Possibly, have you followed all wires from the front actuator. Don't know if the push button 4x4 has one, but my floor shift 241 had a switch on top of the transfer case that sent power to the actuator when engaged that went bad and I replaced

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The 243 has one as well. I replaced it along with the front axle actuator earlier in the year when I tried fixing this the first time.

Grrrr I hate tracing wires.
 

glfirefighter144

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The 243 has one as well. I replaced it along with the front axle actuator earlier in the year when I tried fixing this the first time.

Grrrr I hate tracing wires.

Double check that it is getting power, my first replacement was bad and had to buy a second

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