High beam problem might be bulbs out. Swap one side with a known good bulb, see what that does. Pull the connector off the stepping relay and put it back on. This will remove any oxidization from the terminals.

Reverse lights. Check to see if the bulbs are getting 12v when they are supposed to.

The circuit boards on the tail lights get strange after enough years. The reverse lights are one such.

The connector for the left light contains the one wire to power both reverse lights. The circuit board foil for the reverse light connector is double the width of the other light's connecting points. WEll, maybe there's a couble wide for the fog lights.

Inside the connectors, which can be opened up, there are two pincers side by side that have the same and connect to that double width place. On my 1988 they are black wires. One pincer brings 12v from the switch up front, the other takes 12v from that double width foil and carries it to the right hand light.

If you swap those two pincers, the one bringing 12v from the front will touch a part of the foil that is not burned or corroded, and you will have a left side reverse light. Worked for me.

To see the foil best use a mirror and a flashlight, since the thing you need to see is on the underside.

Good luck,

Bob

:>)