I need some information about my power door locks. Two weeks ago I bought a 1998 F150 5.4l 4x4 xlt extended cab. My key fob and passenger side lock / unlock switch both work good and will operate both doors. My drivers side door switch works intermittently. It usually works better after the truck had been running a while. Does this sound like a bad switch or relay?

 

I would assume its your door lock actuator in the drivers door. I've heard of people rebuilding/repairing them, but I would replace it. A little of a pain to get to, but should solve your problem. Costs $50 from autozone.

 

Thanks for the reply. I wasnt sure if it would be the actuator or not. Im not ruling it out yet, but i dont want to pull the door apart yet if that is not the fix. The plunger goes up and down like normal when using the key or the passenger switch. Also when i hit the drivers side switch i hear my relay under the dash clicking, but does not operate the locks. That is why i thought it could also be a relay issue. Where is the relay located under the dash? It sounds like its buried behind the radio.

 

Sorry, but I'm really not sure. I thought in the drivers side kick panel but I may be wrong. Swapping in a relay would be a cheap way to rule out that possibility. Worth a shot anyway. Do you have anyone with a similar truck to swap out the driver switch also? Rule them both out before the actuator..

 

I dont really know any one with a similar truck. Once I find my relays, I will just swap out the passenger side and drivers side and go from there. Hopefully that will get me going in the right direction.

 

I just finished up replacing my door switch. That fixed the problem. Also, one of the door lock relays was barely clicking in comparison to the other. It still had continuity but was barely clicking. Since they are really hard to get to, I am going to replace both relays. I will post some pictures of where the relays are located in the next few days. They are underneath the oval dash panel. There is a metal dash bracket that has a relay block attached to it. If you remove that relay block, and the metal dash bracket it makes access to the door lock relays a lot easier.

 

I had the same problem - my driver's side power lock was working intermittently. Replaced the actuator and it works like new.