Toyota Repair: T-100 4 wheel drive will not engage, vacuum hoses, dash light

Question
I have a 1995 T-100 SR5 4 wheel drive.The 4 wheel drive will not engage.I can here a clicking sound but the dash light does not come on and it does not go into 4 wheel even after driving.If I put it in low 4 the truck is in low gear but still not in 4 wheel.Last winter I started having the problem but it was intermittent(work some days).Thanks in advance Joe

Answer
Check to make sure the vacuum hoses are attached to the actuator on the front differential, remove the gravel shield, the actuator is attached to the front differential, make sure the hoses are attached between there and the solenoid on the right inside fender, if the hoses are connected the actuator may have clogged ports, they can be cleaned out in some cases by disconnecting the hoses and using a wire to open up any rust or debris that may be in the small steel lines on the actuator.