I am restoring a 99 explorer xlt. When I open the passenger door, no lights come on inside. All the others work fine, even the lift gate and window in the rear. I have looked for a button sometimes located around the door frame on older cars. Lots of wires in the door. Looks like most are to door locks and power windows. Are they tied into one of these relays? Windows and locks work fine. How in the world do these things work? Is there anything to test? Thanks for any help.