3Questions on an 89'Montero's 4x4, HeadlightWasher, and BackDoor Locker. Can any1 suggest? thx

I have a 89 montero. Its working perfectly except for the 4x4, and back door. When I press the unlock or lock button for the back door, it doesn't do anything. After I press it about 45 times, it works, but only once. Then you have to keep pressing it again for it to work? What could be wrong?

On the 4x4 issue, a mechanic said something about a pin being missing. When I put it in 4x4, it makes weird sounds and shakes a little. Im too scared to test it. He said something was wrong.

And on the headlight washer, my car never came with it. The blinker sometimes didn't blink and I got a new switch for it. The new one came with a headlight washer switch? CAN I USE THE WASHER NOW? Or do I have to buy something else? Thanks. Please respond.

rear hatch is probly a faulty relay or the wiring.............

I have had problems with the rear latch and it turned out to be a plastic barrier they placed under the back trim.Remove it from around the inside latch and handle mechanism and oil your latch and it should work fine.