If the switch is concealed in the door latch--(common problem) Spray door latch liberally with WD40 open and close door many times--then spray with silicone should solve problem If not in door latch- could be faulty light switch or wire grounding somewhere in door switch remove, replace and check wiring
checked fuses, or checked for voltage to interior light socket?
The interior light switch on the ceiling of the car might have them turned off, or there may be some electrical short causing the problem.
When the interior light flashing, check all doors, they might be open or not shut tightly.
the 4x4 might not be engaged right
you might have to take to the ford dealer or READ THE Manual
check your ignition switch.
might need to check your engine soon
The brake light may be blown (bulb) or your brake light switch might not be working.
check the brake light switch it might be sticking. located under the dash connected to the brake pedal
first , check you dimmer knob,turn it up or down to see if that works. if that's not the problem, you might have a bad alternator or some other electrical problem with the truck.the light bulbs themselves wont grow dim with age, they will just burn out.
in your doot jam you have little button it is a sensor it might be bad or it is your computer board behind your radio it also controls your door charm and some interior if not all interior light
he might love being a explorer