Have you ruled out the actual motor itself on the transfer case?

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Yes i have I tried another one from another truck.

 

What about checking voltage at the connectors? For the relays/switches/motor. They are circuit codes, so might be corrosion, maybe oil in the connections, or something else like that. May be something going on within the harness too, but don't want to go there quite yet.

 

I have power at both terminals on each relay block under the hood at all times. The dash switch also has reference voltage at it and is recognizing the commands when being monitored through the scanner. I honestly think that I am not getting the command signal out of the tcm to the relay block which should be a ground to also power down to the tcsm. I havent dropped the wheel liner to inspect the connects under there yet.

 

Are you sure your actually staying in 4wd and it's not just the dash light staying on?
If so, when taking out of 4x4, put it in neutral, then flip the switch, then back up about 30 feet, see if that pops it out.
If not, I'd bet the switch is bad. You don't know it's good, until you try a different working/good one.

 

Yes 100 percent in 4x4. Front drive shaft locked at all times, switch commands are being recognized from the gem when I monitor it through a scanner, as well as brake input and signal from the trans when put into neutral. I can back the truck up 100 feet its not unlocking lol. Im leading to believe my tranfer case module is bad.

 

So just an update. Had some time today to go through some more diagnostics which prove one of two things. Either my 4x4 module needs to be reflashed or is shot. All of my pids are correct and in working order. I can electronically set the truck into 4x4 and 4x4 low with the dash switch. But for what ever reason the module will not command a ground signal to revert back to 2wd. Now i can manually supply a ground from the connector at my module and the truck will go back to 2wd. So I'm doing two things. Im going to have buddy see if he can reflash my module and if it fails im just going to put a ground switch to that circuit and call it day. I'll let you guys know what happens.

 

 

Did you replace the transmission transfer case differential lock-up solenoid located on the passenger Side of engine compartment near wheel well? That is what fixed my codes 1832 and 1876. Simple and cheap fix. Mine would either not go into 4-wheel mode or not come Out of it depending on its temperament....

 

The solenoid on the passenger side soley controls the vacuum for the front hubs to auto lock. I ended up taking the control circuit for my 4low to 4high relay and tapped in a momentary switch to ground so that i could get it out of either 4x4 setting to 2wd. The truck had zero issues going into 4x4 and low it just wasnt sending a signal to come out. Everything works now. Not like factory but damn close. Beats spending 200 for a firmware update if that would even have fixed it.

I put the switch right next to the obdII plug and used the same grounds that the 4x4 module uses. Clean and no holes in the dash.

 

Just a guess as mine wouldn't go in to 4X4. I had to replace the vacuum module as shown in this video

Easy and cheap. I didn't read anything about you looking at the vacuum lines.

 

Yea I seen that exact same video. Mine where locking in fine and that solenoid wouldnt stop the transfer case from ever changing 4x4 modes. Atleast it shouldnt. Thank you for your advise tho.