Alright guys im stuck and want to ask before I proceed. 1999 Jimmy.

Here is where it started.. A few months ago I had post on here about a misfire problem and during that time I had discovered the vacuum line was off the diaphragm that pulls the cable under the battery. I put it on and didn't think much about it and don't know how long it was been running like that. However a few days later I decided to check the 4wd and it would just blink and go back to 2HI if I tried anything else. It would go in Auto 4wd. Then there was no lights on the switch. We got a salvage yard switch and it went back to the same issue with not wanting to go into 4HI/LO. We went ahead and parked it.

It has sat for a few weeks and today we tried to work on the 4wd and decided to see what the Diaphragm was doing with a vacuum tester. Worked just fine and pulled the cable and the front wheels would turn on the lift. Well we have no lights on the dash switch. They all light up when you turn the key but when you start up the vehicle they all go out and will not come on. The TCCM does quite a bit of clicking. I checked it for corrosion or damage but it was fine. I see people talking about a ground wire under the drivers door but do not see one. Tried the battery and fuse unplug but no go. We put a NEW switch from autozone but no luck. Never know because I have gotten bad parts before from junk yards and auto stores. When we had it on the lift we also discovered the front drive shaft electric plug was left unplugged. We checked the sensor in the front Diff and it turned out to be ok. We bypass the vacuum switch in the hood and hooked the engine vacuum to the diaphragm because of the snow we have and 4 wheels will turn on the lift fine but on the ground they won't.

So here I am. Any help is appreciated because I know this can get expensive when you throw money at it.