99 Tahoe 4x4 not working

[jeff ashworth]

My Tahoe does nothing when I push the button to lock in T case and front diff. , I have changed the shift switch, shift motor and front actuator, and still nothing. I can pull the fuse out of the 4x4 spot in fuse block and when I put it back in I hear a noise in the T case control module behind the light switch in the dash. does that mean it is bad or what?

 

[Big Mama]

Welcome Jeff this one’s out of my wheelhouse but others will jump in soon. @wjburken may be of help.

 

[wjburken]

My Tahoe does nothing when I push the button to lock in T case and front diff. , I have changed the shift switch, shift motor and front actuator, and still nothing. I can pull the fuse out of the 4x4 spot in fuse block and when I put it back in I hear a noise in the T case control module behind the light switch in the dash. does that mean it is bad or what?

What do you mean when you say you changed the shift switch? Are you referring to the push button switch assembly on the dash?

 

[jeff ashworth]

yes the push button switch in the dash

 

[wjburken]

yes the push button switch in the dash

I hate throwing parts at a problem so I may ask a lot of questions. Others may chime in as well, which is nice, to get some different thoughts on this.

What brand of selector switch did you put in. Dorman and other aftermarket brands have a reputation of premature failures so I try and stick with OEM if possible for mission critical parts.

When you press any button on your 4WD selector switch nothing happens, correct? Do the indicator lights change?

Do you have a way to verify that you are getting voltage out of the selector switch?

I’m looking for the pin-out for the Transfer Case control module to see where you should check for voltage going into it.

 

[wjburken]

Have you checked both fuse #2 and fuse #24?

 

[OR VietVet]

Run tests like has been recommended and then you may find this is the culprit. Unless this is the shift motor you are talking about:

https://www.rockauto.com/en/moreinfo.php?pk=2002474&cc=1353721&jsn=2316

Or maybe this:

https://www.rockauto.com/en/moreinfo.php?pk=6355122&cc=1353721&jsn=2323

But please do some tests and there is recommended tests stated here by Wade and also found on you tube.

Plus, as part of the testing/inspection, make sure all connections are clean and tight and none of the spades pushed out of the connector housing.

 

[jeff ashworth]

well thanks you all for the helpful info. I have replaced all the other parts except the Transfer case control module and so far I have not found it in the dash.

 

[wjburken]

well thanks you all for the helpful info. I have replaced all the other parts except the Transfer case control module and so far I have not found it in the dash.

This picture and link might help point you in the right direction.

https://www.google.com/amp/s/repair...ule-located-at-in-my-1999-chevy-tahoe-058.amp

 

[jeff ashworth]

I found the TCCM under the dash, is there any way to test that TCCM before i buy one of them like all the other parts I have been throwing at it. well I went and took the TCCM out is there a way to test it, numbers on it 15049679- 33870 TZ4EH1609428KK- 17:41-05.

 

[wjburken]

I found the TCCM under the dash, is there any way to test that TCCM before i buy one of them like all the other parts I have been throwing at it.

Try and find someone with a Tech-2 or other body-directional scanner to see what’s going on.

 

[dnt1010]

If this were my +20 year old truck I would make a run to my local salvage yard and pickup the part that I needed from a donor vehicle on the cheap. At 20 years old there will be numerous donor vehicles available. One big advantage of doing this is you that you get to see exactly what holds the part in place, making the swap into your vehicle super quick and easy and without unintentional breaking of plastic clips/plastic plugs etc. Just my personal preference as my vehicle is not going to be running in the 24 hours of Lemans and does not need everything brand new. Man I like that Ford vs Ferrari movie if you have not seen it go rent it now.

 

[Fless]

Try and find someone with a Tech-2 or other body-directional scanner to see what’s going on.

^^^ THIS. It's the only way I was able to figure out what was going on with my '04's 4x4. It didn't have a 'Service 4wd' message, nothing indicating it wasn't working properly, but we were able to exercise the functions and determine what was not working.