Sometimes the rear door locks won't work when you use the key-less entry buttons. My father-in-law has a 2000 and a friend has a 1999 and they have experienced the same problem. That is it!
Unbelievable truck, I have owned 3 F150's and recently purchased a 27' camping trailer. Took it on a week's vacation and didn't like the 8mpg it got in the Texas Hill Country. This truck gets 15mpg with or without the trailer on it. Shifts good, runs good, rides good, tows good, comfortable interior, it's our new family car. We would rather take it anywhere than my wife's SUV.
I have the same "situation" with my door locks. I think you just have to hit the button twice to open the back doors.
Something tells me that I read that or asked the guys in my local service department. It does seem a little weird that we all have the same problem though.
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