4x4 high not working

Nothing happens when I shift into 4x4 high, but when I put it in 4 low the light comes on and it works fine. Do I need a new transfer case?

 

Get on a gravel road, put it in 4x4 high and try doing a burnout. If at least one of the front tires burns out, its working haha.

 

I have done the burnout test and my front wheels do nothing unless I shift into 4 low.

 

will it go in to 4hi after shifting to 4lo first there might be something misaligned in the actuator

 

yeah, or maybe you have a wiring problem where the hubs are not locking when the shifter is in 4 high. The problem is most likely the hubs and not the transfer case.

 

I did not know that. I always thought the hubs were locked by a switch when you put the lever in 4x4.

 

On ADD, the axles are turning all the time. That's part of the reason for switching to manual locking hub if you are going to tow the truck behind an RV a lot or if you put an automatic locker in the front diff.

I can't see how there could be anything wrong with the Tcase itself if it works in 4lo. The problem must be electrical. What is it that actually occurs when I click the 4WD button on the Tcase lever? All that moving the Tcase lever manually does is engage the low range gears inside the Tcase doesnt it? 4WD is already engaged.

 

Its probably the switch for 4hi. There should be two switches, one that tells system when you in 4hi one that tells system when you are in 4 l. I bet the switch for 4hi is busted.
EDIT: I am assuming you have ADD right. And I am talking about switches (aka shift position sensor) inside the transfer case.

 

Ah, so no button. Is the case itself different between autos and manuals?

 

Thanks for the drawings. Those were very enlightening.

Looks like mine has some sort of actuator whereas the OPs has a shift fork/shaft assembly with a spring. I withdraw my comment that it has to be electrical. In fact, from looking at the drawings it looks like something is going on with his front drive fork/spring/shaft assembly.