well 4wd didnt work for longest time, hubs were not engaging, well was messing around pulling a dead blazer today went to put it in 2lo (bc well i figured hubs wouldnt engage so hell lets see wat 2lo is like) and outta no were my 4wd works. so i put it back in 2 hi and start to pull blazer down the road (pos 10 bolt self destructed) and 4wd light was still on for about .5 mile then turned off and would flicker at me for about 30secs on and off.

so wat was happening when the light was flickering?

 

We don't have hubs that lock in; we have whats called a CAD (central axle disconnect) and a good place to find info about that and how to diagnose the cad are in the service manual in the diy section, section three.

 

either the vac cad and associated collar is not moving properly, or the indicator light is malfunctioning. start by disconnecting the electrical connector at the cad, and spray it out with wd40 or electrical cleaner to get the mud, dirt, salt out of the connector. if that doesn't fix it, test/replace the contact switch.

the contact switch is just a little spring and ball plunger. the fork slides over and depresses it. the spring is supposed to reopen it. its just a 2 wire continuity switch. you can jumper the plug to turn on the light in the dash. you can test continuity at the switch in 2wd (open) and 4wd (closed). it probably all rusty...

the best way to troubleshoot is to put it up on 4 jack stands where you can run the engine and vacuum controls to the drive line.

http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm

 

It could be a vacuum leak under by the transmission skid plate or mud in the vacuum lines.