1992 Grand Marquis

The fuse (#9) for our Instrument Panel lights and Tail lights blows after the car sits out in or is driven in the rain. Inserting a new fuse usually resolves the problem until the next rain.

We have checked the seals on the tail lights, and they seem good with no water accumulation. There does not appear to be water under the hood nor in the cabin. Our mechanic had the car for 3 days and was unable to find the cause. He returned it unrepaired with a comment to bring it back when it next occurs.

Please help!!!!