Service 4wd issues

[Big Block 88]

I didnt see that thanks cocoa. Im so electrical stupid i will look into it though. Ive replaced everything but the tccm and the transfercase shift control i guess called the encoder motor.

To renexplain what i have goin for all u smart wireing folks.

The shift lights in the push button all light up with the ignition on run then they go out and only 2hi stays lit. (Like it should). I then press 4hi and the transfer case shifts audibly i get under and grab the drive shaft and it is locked in with the rear shaft. So the transfer has done its job. But the truck still has no power to the front end.

I pulled the diff shift modul or actuator from its housing and have my pops push 2 hi. The actuator doesnt respond. He then hits 4 hi and it doesnt respond. So the issue is deffinately in the front end. I have tried 2 new actuators niether fixed it. The wires look to be in grear shap and the connectors are good. All fuses are good and replaced.

Im just at a loss here. I have to figure out what triggers the front end to kick in. What tells the actuator to move and lock the front end? I would assume that the tccm is fine as everything seems to be doing what it is supposed to minus the front end. I am thinking its a bad wire or ground. But how do i find it? I have removed the grounds to the chassis and cleaned them all and still no help.

 

[Big Block 88]

Okay new discovery. I tested continuity i didnt have it from the ground wire (the light blue wire larger gauge than the others). So i stripped a bit back grabbed a jumper wire and hooked to the blue wire. The other end i grounded to the steering stabilizer bolt and bam the little actuator came to life. Sooooo. Now what? How can a trace that blie wire? Its wrapped up tight in the factory look and i dont want to undo it all. Does any one have a schematic thay shows where thay blue wire goes? I would need it dumbed down as much as possible for an electrical retard

 

[x MadMAX DIESEL]

Front axle switch says it grounds at the body mount bracket on the drivers side front mount


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[Big Block 88]

I agree but i have ground that thing to shiny metal and damn newr polished the terminals that conect there

 

[Hot COCOAL]

I agree but i have ground that thing to shiny metal and damn newr polished the terminals that conect there

:baby:Call me simple, and I typically don't cut corners or leave things stuck together with bubble gum, but, if you got it to work by using a jumper wire to a new ground point, you figured it out, right? So what's the hang up?
you know the right thing to do is you need to open the loom and follow that wire now:angel:

 

[Big Block 88]

If it was as just a ranch truck i would be fine just leaving it hooked up that way till i had more time. But this truck is too nice for that. I Figured a good schematic would let me see where the other end of that wire is. Im assuming there is a junction for the grounds somwhere there. Just cant see them.

U less the tccm is not sending the signal to the front end and me jumping it is just bypassing that command?

 

[x MadMAX DIESEL]

The schematic says it grounds there to dirty type 21 post. Which is that body mount


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[x MadMAX DIESEL]

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[x MadMAX DIESEL]

Was it hot with it in 4x4 or 2wd?


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[Big Block 88]

Thats awesome ben thanks man. It has to be a break in the wire then? I guess my biggest question is. What tells that front diff actuator to kick on and engage? Is there a simple switch of sensor on the transfer case that i am missing?

Btw thanks a ton for the help guys! Im sorry im asking so many questions but i really do suck at dc stuff

 

[Big Block 88]

The switch was flashing trying to get into 4 but i was by my self so i couldnt see if the light lit or not for 4 wd

My dad is back here now and will have him sit in the truck while i do it again

 

[Big Block 88]

My jumper wire is engaging the front axle acuator no matter what is selected 2 or 4 wd. When dad pushes 4 hi the light will flash the transfer shifts but nothing happens up front then use my jumper wire to ground and the front engages and the light stays lit for 4hi. But if i pull the jumper off the front end unlocks.

 

[x MadMAX DIESEL]

I was jw if it opens and closes the ground to move the solenoid. I don't have a full schematic to see and I don't have a multimeter to test. I was just thinking that might be since the wire is blue there and there's not a blue wire at ground block. Was there a thick light blue wire on the switch?


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[Big Block 88]

I will look i never thought to look there. Is there a junction somwhere where all the grounds come together?

Im still trying to figure out how the system works. If i knew more about it i wojld understand better what is and isnt happening.

Like if the transfer case is doing its job and the front is doing nothing im curious what triggers the front to kick in? There must be somthing that sences the transfer case position and then tells the front axle to lock in.

 

[x MadMAX DIESEL]

It seems odd to me that a blue wire would be a ground


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[Big Block 88]

Yeah im not sure it is. Like i said my dc understanding is so minimal i dont get it.

Maybe the blue wire isnt a ground at all and im causing the short to ground (which is how the actuator works i believe). I just need to figure out what triggers it and where that harness ends up. I traced the harness itself yesterday but i still havent been able to make myself open up that nice factroy wire loom. But thats the next step i suppose im just really hoping there is a simple signal sensor or sender that im not seeing

 

[x MadMAX DIESEL]

It might be all one wire from the tccm and break out at the front axle and transfer case, so they work together


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[Big Block 88]

TCCM is on the passenger side and on the firewall correct?