Fairing Crack

I rode my 1982 Goldwing in 40 degree weather, and parked it in the garage overnight.

Next morning there is a 4 inch crack on the inside of the fairing -- not the fairing itself, but the plastic housing on the inside of it.

This original equipment is pushing 25 years old, but I was still surprised to see it crack like this with no warning.

Any suggestions on repair?