4WD not engaging.

[Cary Coleman]

I have an 04 Tahoe, LT 5.3, Vin Z with the 4 button selector on the dash. My 4WD is not engaging in any mode. I bought the vehicle used and noticed at night there was no dash illumination on the selectors so thinking that I replaced that unit, however, I still cannot get the 4wd to engage, though I can at least see the selector switches in the dark now. Also I checked related fuses and they"re good. Before I start further troubleshooting, what is the logical progression for proceeding? It's not throwing any codes pertaining to the transfer case or related parts.

Thanks in advance

 

[Cary Coleman]

I have an 04 Tahoe, LT 5.3, Vin Z with the 4 button selector on the dash. My 4WD is not engaging in any mode. I bought the vehicle used and noticed at night there was no dash illumination on the selectors so thinking that I replaced that unit, however, I still cannot get the 4wd to engage, though I can at least see the selector switches in the dark now. Also I checked related fuses and they"re good. Before I start further troubleshooting, what is the logical progression for proceeding? It's not throwing any codes pertaining to the transfer case or related parts.

Thanks in advance

So it turns out after some research that and watching some trouble shooting videos and reading some comment on sure track that it was the transfer case control module. After 15 minutes of getting the old one out and the new one in, the 4WD is working fine now. The key indicator was that there was no service 4wd light and no codes were showing up on the OBD scan.