I apologize in advance if this has been addressed before- my search skills may in fact be lacking.

'88 vert. I replaced both wiper and headlight switches with reman units from 13Betc. I've had the cold solder joints on the logicon redone- it works great now. I replaced all the bulbs in the cluster with LED's. Still, when I'm driving all dash lights- including the logicon, headlight & wiper switch- go out. The only remaining working lights are the turn signal indicators, high beam indicator, and whatever position the HVAC is currently set at.
Any ideas?

 

It seems like all those lights are controlled by the headlight switch. Are idiot lights, shift-up light, clock still functional? If yes then it most probably is the headlight switch having a bad contact. Maybe re-plugging it will help, otherwise it could be internal, or in the harness.