The headlight module on the '90 is a one year only affair, so you might have a hard time finding a good replacement. However, I think the internals are pretty similar to the earlier ones, so if you open it up and resolder the terminals you have a pretty resonable chance at bringing it back to life. Since the one you have doesn't work, nothing lost in trying to salvage the old one. Follow the instructions here and just sort of adapt them to the module you have.
Your module is located under the dash on driver side, between steering column and kick panel. Black box, about the size of a cigarette pack. It is held in place by a metal clip. It has a wire connector going to it.
there is someone out there who rebuilds these. i bought two from him over the years, and they work perfectly. Let me know if this is the way you want to go.