Toyota Repair: 4*4 light not coming on...., vacuum pipes, inner fender

Question
Question
Hello,
I have a 1994 4Runner (five speed).  When I shift into 4X4 mode (High or Low) it easily shifts into the desired position, but 4X4 light doesn't appear on dash.  

Can you give me some tips on how i can find the section i need to repair... Everything seems to work and no noises. When i move to 4*4 i can hear a relay coming in so i think the transfer case switch is ok but the light will not come on..

Any help would be fantastic given i am in Costa Rica..

Cheers

Dean


Answer
The problem is in the front differential, the switch that turns the 4x4 light on the dash on is located in the front differential, there is a vacuum operated actuator mounted to the front diff, make sure the vacuum hoses going to it are connected, the hoses come from a vacuum switching valve located on the right inner fender. If the hoses are attached the actuator vacuum pipes may be clogged with rust and debris and cleaning them out may help, the actuator can be removed and tested by applying vacuum to the ports to see if it moves.