I just bought a 2002 F150 King Ranch and the keyless remote alarm works but not the door lock. Bought a new battery not that. Any ideas?

 

check the wiring...it could be a bad splice. All the wiring should be tucked up under the drivers side footwell. Is it an aftermarket alarm? it shouldnt be if its a king ranch unless the previous owner put in an alarm.

 

Do the power locks work when you use the button on the door? Its pretty common for the power lock actuators to wear out. In fact I need to replace the one in my passenger door.

 

I think it may be problem on single line. Because the same problem arises on my truck. It will just not activate the locks. not even the unlocking when the truck is turned off.