I have a 2004 Ford F-150 XLT 5.4L V8. When I was getting ready to leave work this morning I noticed that the rear exterior light kept coming on, I thought maybe a door was not closed tight. I walked around and shut all the doors, drove home, parked, turned off the truck, locked the doors and went inside. A few minutes later I look outside to see that it is still doing it.

It appears that it is in a cycle where the mileage illuminates on the dashboard, then the interior and exterior rear lights come on, it makes the "beep" as if a door is open and then displays check gauges message on the odometer. The cycle then repeats.

Any insights?

 

Are your doorsills full of water?