4wd issues

[jrawk1120]

I have a 1999 Tahoe and the 4wd has stopped working. When I press the button, it will blink for a little while, and either turn off, or go back to 2wd. The service 4wd light is also on. When I do press, I don't really here anything trying to engage, but I am always by myself when I decide to try and diagnose it.

 

[BattelWagun]

turn on the ignition, but don't start the engine. Then try putting it in 4WD, when you press the button, you should hear the actuator working (this is best done somewhere quiet, like a closed garage) If you don't hear anything, the first step is to get your actuator motor checked.

 

[SunlitComet]

The np8 t-cases which you should have actually have trouble codes that can be pulled with the right scanner. Try a local part store or shop and ask if they can get the code and post it here. On a side note if you have tranny in nuetral and select 4LO and the 4LO light just blinks and you do not feel a kick in the ass then I would go after the shift motor. But the code first would be preferred so as not to just throw money at it.

---------- Post added at 04:24 PM ---------- Previous post was at 04:18 PM ----------

Also note the system uses two fuses. Check the ATC 20A fuse in underhood box.

---------- Post added at 04:25 PM ---------- Previous post was at 04:24 PM ----------

That is your motor/motor brake power supply.