Auto 4wd Problem

[Harry Pluta]

Hi all,

We went from a day with 50 degree temps and rain, to single digits with a sub-zero wind chill overnight. My 1997 Tahoe with auto 4wd is now acting funny. When I start the truck it is "stuck" in 2wd, the red "Neutral" indicator light is one, the 2wd light is on, and the 4wd High ( I think ) light is on. I cannot get it to shift into 4wd or 4wd auto. These lights go out after a few minutes of driving.

Has anyone seen or heard of this on a '97 and is there a fix like on the newer models ( Pulling the TREC fuse on a newer unit is supposed to reset it.)

Any help is greatly appreciated as the roads are getting bad here!

Best regards,
Harry

 

[loulblades]

To reset the controller on my 96 I disconnect the negative battery cable. I have been told it takes about 30 seconds but I have never timed it.

 

[Harry Pluta]

Thanks, I'll try that this evening.

-Harry

 

[tim@sp]

I was told by a GM mechanic that you need to touch the pos. and neg. cables together to reset the ecu when I changed my encoder motor.

You must have them both disconnected to do this obviously.

 

[loulblades]

I am curious, which positive and negative cables are you referring to?

 

[tim@sp]

The ones at the battery

 

[Harry Pluta]

OK, no joy on that one. Any other suggestions?

 

[bowhunter22]

So you are saying all the lights on the 4x4 control switch are on when you start it. Then they all go out after a miniute or so. (sounds like the control module)

 

[Harry Pluta]

So you are saying all the lights on the 4x4 control switch are on when you start it. Then they all go out after a miniute or so. (sounds like the control module)

Three of the five lights go on. The red neutral, the 2wd, and ( I think it is ) the 4wd High lights. Then after a while only the red neutral light is on. If I touch any of the buttons all three light up again.

What's one of these modules run, anyone have an idea?

Thanks,
Harry

ps; Took an hour to get out of my alley this morning, as good as this thing is in the snow as a 4wd, that is how bad it is as a 2wd, :sad:

 

[bowhunter22]

Not really sure,, But I know you won't like it.