I took my truck out for some trail riding and when the time came to shift into 4X4HI the 4x4hi light comes on but the transfer case doesnt kick into 4x4HI. I tested the 4x4LO and the transfer case kicks in and works just fine. BTW I did do a search and nothing came up.

Thanks

 

I was thinking solenoid, but then I just thought that the low probably wouldn't engage if that were the problem.

 

In your case, the transfer case is not the problem. If it goes into 4lo, it will go into 4hi.

 

well the transfer case might go into low but it might be 2wd low if the case isnt working right try spinnin the tires in low to see if it is in 4wheel

 

with the engine off, go to the front axle and try to turn each axle shaft. The one that turns needs a new hub lock actuator. The axles are locked in by default (no vacuum). Then check your 4x4 vacuum solenoid on the bulkhead behind the battery on the right side. It should have a shield over it to protect it from water intrusion. Guess what happens if it's raining and the solenoid vents the vacuum lines??? I've seen the vacuum reservoir fill with water and freeze in winter, thus cracking the reservoir open. The reservoir is behind the battery.