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Relays
There are already lots of relays in these cars and there is no reason why a few more can’t be added. An easy one, and of instant benefit is the headlights. You can even buy complete kits to do it, but the individual components are easy to source. In a nutshell, you use the existing headlight switch and circuit to activate a coil in the relay so that fresh power (usually taken from the solenoid) is fed to the lights. One relay does high beams and another low. The only other thing needed is a type 1 circuit breaker to protect things. Don’t use a fuse because if it blows, no lights.
The rheostat to dim my dash lights gave up the ghost, so I used power from the tail lights to energize another relay. I also installed a dimmer from an RV supply house so the bulbs wouldn’t be too bright and a lower voltage will extend the bulb life.
Windows are a bit more complicated, but still easy to do, especially the rear. Pick up a triple connector set that matches the one on the motor. Plug the male into the existing chassis harness so that the power from the switch is now routed to the relays, one wire is up and the other down. Use this to activate the coils in the relays. Fresh power (once more fused) is fed through the relay contacts and then back down to the female connector that is plugged into the motor. The existing ground should be looped between the two new connectors. It’s important to use the existing because there is a resistance in the wire so that the voltage to the motor drops as the window reaches the end of its travel. This slows the motor a bit so the window doesn’t slam into the stop.
The fresh power for each application should be fused and there should be a diode across the coil in the relay, but that’s about all needed.
Let me know if there is any specific info or photos that would help.
Terry
64HT