1999 suburban 4WD engaging problems

[VargasB]

I have a 99 Suburban with the Electronic push button switching to/from 4X4 to 2X4 (the four selection dash control options are (2HI, 4HI, 4LO, AUTO 4WD)
My wife noticed that when she presses one of the buttons lately to go into 4x4 it does not swtich or light up, and there is no engagement of the 4WD - no lights are on also. Is there a fuse (I looked and could not find one in the fuse box) or should I be looking somewhere else. All cables underneath appear to be plugged in. Is there something else I should be checking for?

[777stickman]

There are 2 fuses to check. All are in the instrument panel fuse block (left side at drivers door).
1: 4WD-20amp-#24
2: T CASE-20amp-#2
Post results and we'll go from there

[myhd]

My 1999 Yukon did the same thing. It was one of those fuses.

[VargasB]

Thank you so much for the information. It took me a while to figure out that the fuse box was at the end of the dashboard, of course right there where you said it was. The 20 amp fuse for the T CASE was pulled out and a new one put in, then once the new one went in I could hear the click down below and when I turned on teh key the klghts came back. The fuse looked good though, I could nto se where it showed that it had burned out.
Again, much thanks to both who responded

[Huntmastr1]

Does anyone know what is causing this fuse to blow? Also what brings on the "Service 4X4" message intermittantly?

Thanks,
Jeff

[777stickman]

Originally Posted by Huntmastr1

Does anyone know what is causing this fuse to blow? Also what brings on the "Service 4X4" message intermittantly?

Thanks,
Jeff

Jeff: Fuses blow due to a short to ground, either in the wiring or in the component they power. The "t-case" fuse powers the 4wd control module and the t-case shift actuator. The shift actuator is prone to failure and replacement usually fixes most problems. However, these cars have codes in the computer that need to be read to properly diagnose these problems before you start replacing expensive parts.

The "service 4x4" light comes from the t-case control module sensing a malfunction in the system. What kind of a malfunction?? You can only find out from reading the trouble codes.