Chevellestang

02 king ranch super crew. Both front doors won't lock or unlock with buttons. How should I start searching for problem? Could it be both actuators or relay? I'm not very good with electrical stuff but mechanically inclined.

mbb

Door lock actuators are known problem

The motors have a thermal overload to protect from keeping button pushed
This overload fails

You can open actuator and bypass overload with tinfoil, and glue/tape/zip tie case back together. All you do is wrap overload with foil and reinsert it

It might work for a year or two

Honestly, its such a pain to take actuator out and get linkage attached again, its stupid not to fix it right . ( Imagine trying to get linkage and actuator to go together by feel inside door, for 45 min.). You will regret the rigged solution eventually. Actuators can be bought for $30 each.

OhioLariat

Is this a case where they did work, but now suddenly they don't? If so, both actuators failing at the same time seems unlikely . Ford's 5-wire setup for the locks is tricky. For instance, the passenger side lock won't work from the driver-side control if the pass-side switch is unplugged. ( I found that out by chance. )

Some basic troubleshooting should identify the problem. I assume you know this, but the first thing to check is fuses. (You'd be surprised how many people don't look at the simple stuff first.) The next would be to check for voltages at the harness, and switch operation. Do you have a multimeter or test light? I can pull up the wiring diagrams tomorrow (if you can't find them online).

Andy

Chevellestang

Thanks guys. I will check the fuses tonight or at lunch and I will touch base with you then. I could definitely use some guidance on checking the voltages. I have a multimeter but really dont understand how it all works or exactly what to hook each end up to. Ill get back to you on fuses.

Chevellestang

Ok. I found the fuses and the fuse is good. Should I first pull out the switches and test them? If so, would you guys mind telling me how to make sure the switches work. I do have a multimeter. I appreciate all the help! I just bought the truck as a project and so im not sure how long both have not been working or if they went out at the same time. Im sure it has keyless entry, but doesnt have a fob. I am going to order an aftermarket one soon to work on that but I would like the actually door lock buttons to work too.

OhioLariat

Fusebox diagrams can be found in your owner's manual. If you don't have one, you can download a PDF copy for your truck using THIS LINK.

Let us know what you find, and we can go from there.

EDIT: Whoops!

Andy

Chevellestang

yeah i found the correct fuse and the fuse is not blown, it must be another problem.

F150ken

As mbb said, actuators are a known problem. Both mine went out at close to the same time. Pain to do, but my eBay replacements have 5+ years on them.

OhioLariat

Since you inherited the problem, it's entirely possible the actuators are, indeed, shot. Best course at this point will be to first test power at the wires going to each actuator under lock and unlock conditions. You can use a safety pin to pierce the insulation of the wires, set your meter to read DC voltage (200VDC setting is a common one), and connect your meter leads to the pins. If you have one, a test light may actually be better in this case, since you're not worried about polarity (you're just checking for the presence of voltage), and it's easy to see the results. Just be sure to check it on a known good 12V source first. I speak from experience on that one. You should have power at the actuator leads when pressing <lock> and <unlock>. If using your DMM, and voltage is there, you'll notice it the voltage is positive in one state, and negative in the other. If you have voltage, then the actuators are your culprit(s).

Andy

Chevellestang

perfect. I will do some testing today and tomorrow and as soon I know more I will respond. I appreciate you spelling it out for me. I will see if the switches are good and if they are getting power to the actuators, then we know the actuators are bad. I kept thinking that the switches were bad because i couldnt hear the actuators even engaging.