4x4 not working, more details in thread

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lkfldredneck

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A while ago when i got the engine running, (january 1st) i moved the truck under its own power for the first time. When i needed to move the truck from its sitting spot, i needed 4x4 because my yard was complete ice. Popped it in 4HI when i was warming it up and it worked, stayed in 4 until i threw it back in 2. When i needed it again, it wouldnt work, so i had to move the truck with my plow truck and thats a pain in the ass. I just thought it was too cold for the TLA to work cause it was -30*C that day. Waited till it warmed up and at +10*C it still wouldnt work. Took the plug off the TLA to test for power.. nothing. Tested the wires at the t-case switch and it went like this.

Blue wire probed with pos, green wire with ground. Around 3 volts.

Brown wire pos, green wire ground.. nothing.

Blue wire pos, brown wire ground, around 3 volts.

And vice versa for the one above it was around 3 volts.

I know that the blue wire is the power to the TLA and the brown is main power, but is green just the ground?

And no the fuse isnt blown.

Anyone??

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SCOTTYINWV

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Pull the plug from the t case switch and cross over the 2 terminals on the pigtail. See if it engages.
 

SCOTTYINWV

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I don't have a t case switch, so the wires that ran from mine are on a toggle switch. Instant 4x4, but mine is electric not thermal. It will still work to test it though.
 

RHamill

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So I assume you have a thermal actuator? Pull actuator, engage and see if it heats up and actuates. If not, you need an actuator. Same goes for an electric one.

Could be a transfercase switch on top of transfercase, the ball get stuck in the switch.
 

lkfldredneck

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So I assume you have a thermal actuator? Pull actuator, engage and see if it heats up and actuates. If not, you need an actuator. Same goes for an electric one.

Could be a transfercase switch on top of transfercase, the ball get stuck in the switch.

Thats what a TLA is, thermal linear actuator. And i tried all of that. I pulled the switch plug and probed it, thats were i got the numbers in the OP.

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Mr_Nationwide

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Let me know how that turn out. Mine won't engage what's so ever.
It's on my 98 Yukon that has a "Auto 4WD" button and Neutral light.
 
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