4 wheel drive problem

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Fless

Staff member
Super Moderator
Joined
Apr 2, 2017
Posts
10,468
Reaction score
20,803
Location
Elev 5,280
Look in the glovebox for the RPO codes. They're on a sticker and there will be 30 or 40 of them. You should have an NP1 or NP8 there, or something similar. That code will tell which TC.
 
OP
OP
R

Roger L

TYF Newbie
Joined
Jan 9, 2019
Posts
24
Reaction score
2
Look in the glovebox for the RPO codes. They're on a sticker and there will be 30 or 40 of them. You should have an NP1 or NP8 there, or something similar. That code will tell which TC.
I found NP5 and NP8
 

Fless

Staff member
Super Moderator
Joined
Apr 2, 2017
Posts
10,468
Reaction score
20,803
Location
Elev 5,280
NVG 246 TC, then.

Easy thing to check first is the ground connection that is under the driver's side front seat, just aft of the wheel well. There should be two ground bolts there and those need to be in good shape. Recommend cleaning those two connections first.

To get codes you need a Tech 2 or an advanced reader that goes beyond engine codes. Most of your Advance Autos aren't going to have those higher level scan tools, so you may have to look around for one.

The automatic transfer case control module (ATCM) behind the dash should be supplying 5v DC to the dash switch. If you want to check that the Tech 2 can read it or you can pull the dash switch out and measure it with a voltmeter at the harness connector. (A wonky ground as mentioned in my first sentence can cause voltage issues here.) If you need the pinout let me know and I'll see if I can find and post it.

I know that you have bad switches but those can be ohmed out. Not that it will do you much good if you've already determined that they're bad. See the third page of this PDF for the values, but also note that the full article is for a different encoder motor system and references 8v, not 5v. Your system should be 5v. http://www.atraonline.com/gears/2006/2006-08/2006_08_08.pdf

EDIT: measurement procedure here, starting at about 2:10 into it.


You can also ohm out the encoder motor pins; I should have those values from Dorman and would be happy to share them if you're interested. Just let me know how far you want to dive into this.
 
Last edited:
OP
OP
R

Roger L

TYF Newbie
Joined
Jan 9, 2019
Posts
24
Reaction score
2
NVG 246 TC, then.

Easy thing to check first is the ground connection that is under the driver's side front seat, just aft of the wheel well. There should be two ground bolts there and those need to be in good shape. Recommend cleaning those two connections first.

To get codes you need a Tech 2 or an advanced reader that goes beyond engine codes. Most of your Advance Autos aren't going to have those higher level scan tools, so you may have to look around for one.

The automatic transfer case control module (ATCM) behind the dash should be supplying 5v DC to the dash switch. If you want to check that the Tech 2 can read it or you can pull the dash switch out and measure it with a voltmeter at the harness connector. (A wonky ground as mentioned in my first sentence can cause voltage issues here.) If you need the pinout let me know and I'll see if I can find and post it.

I know that you have bad switches but those can be ohmed out. Not that it will do you much good if you've already determined that they're bad. See the third page of this PDF for the values, but also note that the full article is for a different encoder motor system and references 8v, not 5v. Your system should be 5v. http://www.atraonline.com/gears/2006/2006-08/2006_08_08.pdf

EDIT: measurement procedure here, starting at about 2:10 into it.


You can also ohm out the encoder motor pins; I should have those values from Dorman and would be happy to share them if you're interested. Just let me know how far you want to dive into this.
I appreciate the help, I'm a former mechanic with health issues and can't get around like I used to. I'll try to check the ground first, then check the voltage at the switch. Thanks
 

Sean Collins

TYF Newbie
Joined
Apr 9, 2019
Posts
12
Reaction score
16
I've heard the grounds under the driver side on frame right behind the tire cam break. The ground for the 4WD motor is there. See if anything is going on there
 
OP
OP
R

Roger L

TYF Newbie
Joined
Jan 9, 2019
Posts
24
Reaction score
2
NVG 246 TC, then.

Easy thing to check first is the ground connection that is under the driver's side front seat, just aft of the wheel well. There should be two ground bolts there and those need to be in good shape. Recommend cleaning those two connections first.

To get codes you need a Tech 2 or an advanced reader that goes beyond engine codes. Most of your Advance Autos aren't going to have those higher level scan tools, so you may have to look around for one.

The automatic transfer case control module (ATCM) behind the dash should be supplying 5v DC to the dash switch. If you want to check that the Tech 2 can read it or you can pull the dash switch out and measure it with a voltmeter at the harness connector. (A wonky ground as mentioned in my first sentence can cause voltage issues here.) If you need the pinout let me know and I'll see if I can find and post it.

I know that you have bad switches but those can be ohmed out. Not that it will do you much good if you've already determined that they're bad. See the third page of this PDF for the values, but also note that the full article is for a different encoder motor system and references 8v, not 5v. Your system should be 5v. http://www.atraonline.com/gears/2006/2006-08/2006_08_08.pdf

EDIT: measurement procedure here, starting at about 2:10 into it.


You can also ohm out the encoder motor pins; I should have those values from Dorman and would be happy to share them if you're interested. Just let me know how far you want to dive into this.
I finally got the grounds cleaned up and tested the switch. I'm getting 5 volts to it and ohms test checked out good, still no lights at the switch and it still does nothing
 

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
23,710
Reaction score
34,669
Location
Stockton, Ca.
Probably a bad switch still, buy a oem or get one from a different supplier, if I remember correctly a new oem online is about $65.00 the problem is common with these switches they have a ghost in the machine, sometimes you can kind of make it work by holding down the selection button you want while you start the truck keep holding it in a few seconds then release.
 

Forum statistics

Threads
129,223
Posts
1,812,404
Members
92,325
Latest member
Tom McCormick
Top