Toyota Repair: 4 wheel drive light, vacuum pump, stiff wire

Question
The 4 wheel drive light on my 92 4 runner has stopped coming on. The transfer is engaging but as far as i can tell the front wheels arnt locking in. what needs to be done.

Answer
There is an actuator on the front differential that engages the four wheel drive, remove the front rock shield and you can see it, it is vacuum operated and gets a vacuum signal from a solenoid to operate it, remove the actuator and apply vacuum with vacuum pump to see if it moves, sometimes the small pipes get clogged up with debris or rust, you can try to clean them out with a stiff wire before you remove it and see if that works.
The reason you don't see the 4x4 light on the dash come on is because the switch for the light is on the front diff and if it doesn't engage there is no light, check the actuator and let me know what happens.