4 wheel drive wont engage on 2000 sierra after new encoder motor

[als_sierra_2000]

Looking for some input, I have posted on other sites and no one has replied. My 4 wheel drive wont engage the front axles. I put in a new encoder motor and dash switch. No 4 wd service light on the dash.
Do I need to bring it to the dealer to erase old stored codes that might be in the TCCM and re-program the t-case, or is that just a gimmick. Any real signs that TCCM is bad that someone could share.
Also I took out the ABS fuse due to bad front wheel sensors on the hubs. I put it back, just to see if the 4 wheel drive engages and still nothing the lights just flash at 4Hi. even with new encoder motor on the t-case.
the actuator on the front axle has juice in the brown wire but does not do anything when I switch to 4HI, same symptoms with new front actuator . the front axle does lock in and turn.

Please help if you have practical experience with this scenario...

[gmtech1]

Have you pulled codes yet? That would be helpful to get on the right track.

[Z15]

Have you just been sitting still when you are trying to engage it? What happens if you move the vehicle? I seen a friend replace the front actuator once and he had similar problem. Start truck up, shift into 4wd and nothing. Played with it for hours. I stopped over and he had me sit behind the wheel while he fooled with this and that. Finally I told him, get out from below I going to put it in gear. Did that and moved a ft and the light came on and 4wd engaged. He never thought to move the truck to see if it would engage.

[als_sierra_2000]

thank you both for replying, I'm going to the dealer to pull the tccm codes tomorrow, also thanks for the idea to move the truck once a new front actuator is in. I just tested the front actuator to see if I hear anything by connecting it to the harness and had my wife hit the 4hi without moving the truck....with the new encoder motor I did try to engage the 4hi while moving....

[als_sierra_2000]

update....I changed the front actuator and drove the truck, tried to change to 4hi and the light on the switch just keeps blinking without engaging the 4 wheel drive. No 4 wheel drive service light.. Same symptoms as before...I'm going to the dealer soon to scan the tccm

[als_sierra_2000]

update...went to the dealer today and had them scan the tccm.... no codes showed up on the scanner.. new encoder motor new front actuator and dash switch but front axles wont engage.. 4hi light on button just blinks...bought Haynes Repair Manual 24066...based on the procedure for the nvg 246 transfer case the encoder motor turns a sector shaft into selected mode when you press the 4hi button on the switch, not sure if I can hear that particular function happening....any thoughts..I'm thinking of switching out the front speed sensor on transfer case, but if bad it should show up during scan ?????

[gmtech1]

Without being able to see scan tool parameters to see whats going on, I can't say for sure, but it sounds more and more like a transfer case shift control module problem.

The flasing light indicates a incompleted command.

[gmtech79]

Try cleaning the grounds at the body mount under the driver door closest to the LF wheel. There are two grounds one for tccm and one for ABS. Make sure to clean until you get metal. I've had many 4WD problems caused by a poor ground at that location.

Sent from my Droid X. Typos probable.

[als_sierra_2000]

thank you both for trying to help out, I did clean the metal under those two ground wires, I did some brake line work about a month or two ago and had to take the ground wire off to move the harness around, wish I had tested the the 4 wheel drive prior to doing the brake line work....do you guys know off hand which pin (A, B, C, D encoder harness) should have juice when 4 hi button is set.

http://www.transmissiondigest.com/te...09UpToStds.htm

[als_sierra_2000]

info from the dealer - Cannot engage 4 Wheel drive unit with tech 2
- No Codes Stored