I have a 1999 E150 Sherrod conversion van, love my van. The power locks act very weird. Most of the time it will only lock when you press the lock button, but will not unlock. And this is only front doors and rear doors. But every once in a while the locks work. Also when the side door is open the dome lights do not come on, but when the locks all work, the dome lights work,with the side door. Thank you in advance.

 

Someplace you might check,
At the driver's side door hinge area is where the bundle of wires from the switches on the door pass through to the inside of the vehicle. You can pull the rubber boot/covering out from one end and look for a possible broken wire. The outside may appear ok , but could be partially separated internally producing an intermittent path/connection to the components inside the van. If you pull gently on the wires you may find one that is a little stretchy and that could cause problems like you are seeing.