How to fix a leak on the dashboard

Winnebago had a serious issue with the steel frame behind the windshield rusting badly, which will first cause leaks then will eventually crack the windshield. You can try resealing around the glass but, if you see rust when you remove that rubber trim, the only way to fix the problem is to have the glass removed, the rust dealt with, and windshield installed with new sealer.

Hopefully, your leak is marker lights. Deal with them first and hope that takes care of it.

Probably 75-80% of the dashboard/driving area leaks I've seen over the years have been either marker light cracks/seals or antenna roof penetrations. The others have mostly been front cap to roof seam leaks and not very often, windshield seal leaks.

Ditto on all the previous responses. I went through this on our MH. First the windshield and the rubber strip. The strip is just for looks. If you pull it off you'll see where the windshield should be sealed to the metal framework. I tried several times to seal the windshield without success. I finally bought some 3M trim adhesive. It's a rubber strip, like tape with adhesive on both sides. I attached that to the back side of the trim piece and reinstalled it. That sealed the trim piece to the front cap.

Still had a leak. Marker light gaskets were shot and previous owner had tried sealing around them with silicone. The water backed up inside the cavity the light assembly sits in and eventually went through the hole the wires come through. I made new gaskets, they're no longer available, from some EDPM weather stripping. No more leaks and it's been in multiple downpours.

The outside molding (120533-01-000) on your windshield has nothing to do with keeping water out, it's just there to make it look good

Check your clearance lights.

I would have a professional reseal the windshield.
It may not be bonded properly.