1998 GMC Envoy 4x4 Problem

My 99 Jimmy 4x4 will not shift out of 4LO. I have had this truck for 8 yrs with now problems(61k miles) I took it to a cleanup shop and when i went to pick it up today it was in 4LO and would not respond to shifting out into 2wd nor 4HI. The shop guys say they didn't shift it into 4wd. When i turn the ignition on the button lights light up(test mode) and go out leaving the 4LO light on. When i push one of the buttons(2wd or 4HI) nothing happens, the button lights don't light up or flash at all as if it isn't receiving any signal. I disconnected the battery for a couple hours and then reconnected. I turned ignition on(not starting) put in neutral and pushed the 2wd button and still no response. My truck is stuck there in 4LO until i can trailer it home or to a dealer. Any ideas? Did i miss something here? Thanks for any suggestions you might have.

Did they give it a bath?
Like a lot of water with a high pressure washer?

You might ask them to put it inside overnight and make sure everything is dryed out.
Check fuses and wiring to start with.
Good Luck
MT

Thanks for the reply MT. Yes they did give it a high pressure bath. I had to leave it there last night and it sat outside in 20 degree weather. I may need to get it to a shop to get on a rack to check out all the connections. Thanks.

It may be a connection or wirning wet.
Give it a little inside heat and dry out time
Good luck.
MT