So far several people have ruled out the OVP as the issue and suggested tracing the wiring and finding the root-cause for the fault (the light is telling you there's a problem in the system). So far the OVP has been replaced (even though it was fine), but the wiring hasn't been checked. The car is at least 28 years old and things fail regardless of who owns them and how well they're cared for. How is this the car's fault again?