Okay I have a 96 disco sd no central lock, no fob, when I lock/unlock the drivers door, it locks/unlocks the passenger front door and nothing else. I have tried to turn it hard in either direction with no luck. I have checked all the fuses. I have not checked the relays because the passenger door unlocks with the drivers door. Please help me figure out how to auto lock/ unlock with the key

 

Even the driver door does not lock/unlock?

I would say it's bad lock actuators on the back doors if the drivers lock is working.

You can remove the lock actuator and send 12volts to it directly to test it.

 

I will try that. I just find it strange that all the rear doors don't lock/unkock