[jriera]

In theory lights and wiper are into two different circuits, but I don't have any 1986 electric diagrams.

If I have to guess I will say that some faulty ground is causing all of that, but I'm well known for not being very good at guessing.

Alternator cables and electrical tape do not go together very well, I'm sure that the tape is no longer there.

What is the voltage you are getting when running??