most prob the contacts on the solenoid within the door. you can strip down to clean the contacts but sometimes easier to get one from the breakers. they come as a complete latch assembly. you can find out which front door is causing the problem by disconnecting the passenger door and see if the drivers one still plays up, if it does then theres your prob. The solenoids have a 'check' system to ensure they have operated and if the contacts get dirty on either door then the system thinks the lock has not engaged and tries again.
the other thing to try is to spray WD40 down the cable that goes to the interior door handle as a sticky cable can also cause this problem as the solenoids are working against this if the inside becomes dry. just take the door panels off the front doors and you will see what i mean. Hold the handles up and let the WD40 go into the operating cable.
hope this helps.
Mark - loughton.
October 2009
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