99 F250 LD 5.4 4x4
I have a problem with both door locks. Depress the buttons , lock or unlock and theres a click but nothing happens. Put the truck in gear and both locks lock. I still have to unlock them with the door handles or key. I thought that it might be bad solenoids but why do both doors lock when in gear? Any suggestions?

 

sounds werid im not expert but does your truck have some kind of aftermarket theft system?
cuz i know alot of cars that when you put them into drive they lock
just throwing that out there

 

Here is some additional info on doorlocks. Not only do they click but
they move slightly . If the solenoids are bad it seems strange that
they would move the locks when the vehicle is put into gear.

 

Do some voltage measurements to verify what you're saying. Voltage at solenoid in gear and out of gear.

 

My 2001 f150 has the same issue at times, but before it annoys me to the point of looking for the problem, it starts working again. How lazy we all have become w/power locks and key fobs... Never use the key to unlock the door until the locks started screwing up.

 

Could be a voltage drop from the lock switch that's not happening with the signal from the gear indicator....

 

Both door locks work, but only in gear. That says the problem is COMMON to both sides. What is in common? The locks themselves seem to be functional since they work properly when in gear. I'm looking for a control module. Time for Alldata or Mitchell

 

Same issue. Key will mechanically unlock the doors (Truck has no keyless entry). However from inside the truck, the electrical door switch will only lock the doors, not unlock them. Not sure what keeps the "unlock" part of the switch from working. If I punch the switch real quick the unlock part will work sometimes. I'm looking for a control module also, or I'll check out the actuator next.

 

you must have something aftermarket in there..do u use a key fob made my ford?

What i think it is..is your switch is messed up for the doors..but ur after market puts it into lock which means the actuators must be good..

try this:
throw the truck in gear...should lock it...

put it back in park..should unlock it..
if not try turning the car off but dont open the door and see if it unlocks itself?