4wd Problems

[SHICK]

I was not sure where to put this problem but I could really use some help. I have checked all fuses and they are all good and passing at least 12V I currently don't have 4wd, the lights on the selector do not indicate what drive I am in. It is a new switch as I thought this was the problem. I have checked the power going to the transfer case on the thick red wire and it is 1.4V. I have checked continuity from the transfer case to the tcm and it is good. Voltage coming out of the tcm is also 1.4v on the red wire and the wire next to it is also 1.4v. The wire next to it is in the 12v range. Am I suppose to have 12v going to the transfer case on that thick red wire? Is there any way I can test the TCM in or out of the truck? Does anyone live in the Fredericksburg, VA area have a tester that can help me? I have been without my 4wd for a few months now and it is really getting old getting stuck in wet grass. Any help is greatly appreciated.

Truck is completely stock and there was no service 4wd message.

Keith

 

[chevyburnout1]

Something to try real quick... In the underhood fuse block, pull the ATCM and/or TREC fuse for about 30 seconds, all while leaving the ignition key turned on. Re-install the fuse(s) and see if the 4x4 buttons illuminate/operate.

 

[SHICK]

I will give that a shot when I get home. Thank you.

 

[SHICK]

I pulled the TREC fuse with the ignition on for 30 seconds and still nothing.

 

[SHICK]

I just called the dealer and they want $102 just to throw it on the diagnostic machine. Does anyone know where else I can send it in the Fredericksburg, VA area? All help is greatly appreciated.

 

[chevyburnout1]

If you feel like getting under the dash you should check power and ground at the transfer case control module. It's under the driver's side dash sorta up hidden. I believe it has three connectors running to it.

 

[chevyburnout1]

Shit, speaking of ground... There is a ground on the frame just under the driver's floorboard that you should check/clean. That's where the t-case module gets it's ground. Common spot to not make a good connection.

 

[SHICK]

Cleaned and no dice. Power coming into the transfer case is 1.4v and the ground is solid. Can I pull a tcm out of another truck and put it in mine to see if will work?

 

[THEFERMANATOR]

Cleaned and no dice. Power coming into the transfer case is 1.4v and the ground is solid. Can I pull a tcm out of another truck and put it in mine to see if will work?

The TCCM is not at the transfer case, it is under the dash on the drivers side pretty much right behind the dash switch. Make sure it is getting power and ground before you go any further. Also check all fuses regardless of what they are for. Sometimes a fuse for an accessory can cause other modules to go out(I work on a FORD van that keeps popping the DRL fuse and his A/C goes out).

 

[SHICK]

So can I pull a TCCM out of another truck if it has the same part number and put it in my truck? I will just repost so we are all on the same page. I currently have 12v going into the TCCM on post B. I also checked the ground on the TCCM and it is also good. I currently have 1.4v coming out of posts C & D. I have checked the continuity from the TCCM to the Transfer case and I am reading good. At the transfer case I still get the same 1.4v that I was getting coming out of the TCCM. I have checked the ground out of the Transfer Case and it is clean and good. I have checked all the fuses and they are reading stong on all. Thank you so far for the help.

 

[Alliance1289]

Sub'd. I've got a customers truck that's having some very similar issues after I rebuilt the transfer case. Don't know if its coincidental or not.

 

[chevyburnout1]

Based off that info you gave I would be leaning towards the module. I have never tried swapping TCCM's before but I believe it's worth a shot as long as it's out of another dmax with the same push button shift. Being the same part number would be a plus.

 

[THEREDDEVIL]

There's a little piece inside the actuator motor on the side of the tcase that can break and cause the motor to lose its index or whatever u wanna call it. I actually took mine apart and got it clocked wrong. No lights lit up but the truck was stuck in 2wd. The bad thing is that motor is like 200+ bucks

 

[SHICK]

Thank you all for your input. It does not look like there is anyone in the area than can help out with a scanner or to borrow a TCCM and I am not just going to throw a couple hundred dollar part at it and hope it works. I already did that with the push button selector and that didn't help. Thanks again.

 

[SHICK]

It was the TCM, put a new one in and now everything is good.