The Fuse/Relay box under the hood has a single connector that has power for all three running through it. Check that.
It needs to be checked out . There are many things that can go wrong.
Have you checked to see if the brights are not just burnt out? Rarely do they both go at the same time, but it is possible.
faulty switch
You didn't mention if you checked/tested the low beam headlamps or not.
Have you checked the fuses?
Low alternator output or weak ground connection. Have the alternator checked.
Have you checked the fuses for the wipers? It may be that simple.
in 1986 the headlights weren't fused the likely suspect would be the dimmer switch if it was located on the floor.
If the headlights are halogen, these tend to be sensitive to voltage spikes. Before replacing the headlights, have the electrical system checked for faulty voltage regulation.
have you checked your wires
Check to see if you are getting power to the wiper motor. If you are it is likely the FUSE, but if that's already been checked it SHOULD either be, the wiper motor or the switch, I would guess the motor.
check the connections to the headlights and u might need to take your heater core out and get that checked out. or your belt may be bad or broken.