I just purchased a 2003 F150 supercab. When the door locks try to actuate they just chatter. Both doors do the same so I'm thinking it's not the actuators but it may be a low voltage situation from a bad relay or something similar. But I know nothing about these locks so it could be anything. I would appreciate any thoughts on this.
Thanks

 

mine dont chatter but they wont lock or unlock, my guess is its the relay, cheap replacement, im doing it tommarow and ill let ya know if it works

 

I dunno guys, you might get lucky with a relay, but I doubt it. The actuators are really not that hard to replace and they aren't all that expensive either. I think I paid $60 or so for a pair from eBay. My original actuators failed about 2 years ago, the pass side first and then the drivers side about a month later. I replaced them both about a week after that.

The whole job takes about a hour, you can do it!

 

mine when i first start the truck work once, then they get weaker with every push of the button and they are equal with the power lose, but the relay was my problem