Ford Repair: Windstar Power lock problem, power locks, 1995 ford windstar

Question
1995 Ford Windstar mileage 105,000. I have a problem with power locks in my minivan. The doors unlock perfectly whether by a remote control or by pushing any of the buttons inside (driver, passenger Tailgate door), but will not lock from any of them. It's not a problem with the remote as the lights blink and honk sounds when I press the Lock button, but the doors remain unlocked. Pushing any of the Lock buttons inside also produces no result. Any ideas would be appreciated?  

Answer
John,

There are a few possibilities with this problem, but this is what first came to mind.  I am pretty sure the Windstar will not let you lock the doors if there is a key in the ignition switch. Now, what I believe may be happening is the key indicator inside your ignition lock cylinder may be broken indicating that the key is still in the ignition. Does the warning chime continue to chime if the key is out?

The other possible cause would be a bad lock relay. I am not exactly sure where it is located without a good repair manual.

Hope that helps some.