99 silverado stuck in low

[1BEATK5]

My mom called and said her truck is stuck in what she believes to be low range, and all the 4wd buttons are lit up. It's a 99 silverado 1500 nbs with the 246? The case that has the auto 4wd capability. I replaced the button assembly about 150k ago. I'm thinking Thats what took a dump, but I can't go look at it yet as she lives over an hour from me.

She also said that it was in 2wd when she parked it. It sat for a week. Then when she went to leave it was all jacked up as soon as she started it up. That's why I think its the buttons again, or atleast electrical related. It has 300k miles on it, so who knows wtf is wrong with it.


Anybody seen this before? It sucks diagnosing somthing over the phone, but there are no parts stores anywhere close to her house. So I really need to have a good idea what's wrong before I go.

 

[Stomis]

Sounds like water got somewhere and turned some things on but you're on the wrong coast for that right now...

 

[Blue85]

I was stuck in 4HI in my '05, with all buttons lit up. I pulled the button assembly out of the dash and cleaned the board and buttons (I had some inkling it was wet/dirty, but that's another story). After that everything worked fine. It's very easy to get this assembly out. If she didn't intentionally put it in low range, then it seems plausible that the buttons are to blame.

However, if the controller detects a fault in the actuator or wiring, there may be nothing to be done from the top. Disconnecting the battery might clear it to get back to high range. Otherwise I imagine if it's broken there is some way (for someone who wrenches) to manually trigger the actuator or pull the actuator and turn it back to high range with something else.

You know, I can't remember ever grabbing the floor lever for my NP208 and thinking "Wow, this is soooo inconvenient. It would be so much more reliable to use a control module, gear reduction motors and more crap on my dash."

 

[jake 03]

Those are notorious for the encoder motor taking a dump and acting like you described. The only way to know for sure is to pull the codes

 

[63chevyll]

Same thing happend to me in 06. I pulled the fuse, disconnected the battery, then.connected battery, then put fuse back in. Been good ever since

 

[ktmoutfront]

I had my 01 Duramax go into low range at 45mph. Theft told me it couldn't happen. But it did. The switches were bad.