1997 Ford F-150 electrical

Very common Ford problem. Water leaks through the windshield onto the "GEM" module. That's Ford's version of a Body Computer. It controls all the things that never needed a computer before like wipers, chimes, and lights.

Is it repairable and at what cost

Sorry to ignore you for so long. I overlooked the notice that you replied.

The fix is to have the windshield resealed, but I've heard about people moving the GEM module to where it can't get wet, or they wrap it in a plastic bag. As for costs, we don't get involved with that because there's way too many variables. The first thing is to verify there really is water leaking onto the module. If there is, you can expect to find corrosion on the connector terminals. It's that corrosion that creates short circuits when it gets wet. That must be cleaned off too as part of the repair service.