I am having problems with alternators on my 1977 Volvo 242. The car is now a race car, so the wiring has been hacked to include a kill switch and that may be part of the problem. With the original Bosch alternator it was often necessary to race the engine or drive around awhile before the alternator warning (battery charge) light would go off. I decided to upgrade the alternator to a Denso alternator from a newer model. The alternator (actually 2 of them) will not charge UNLESS I connect the alternator warning light wire directly to the 12V bus. If I do that, everything seems just fine. The alternator seem to regulate properly. Will this cause a problem? I have measured the voltage supplied by the original alternator warning light wire and it seems to lag the 12V Bus voltage by 1 volt or so. Even with the car not running the voltage lags the main 12V buss voltage. I assume this is because the wiring has been hacked up and additional resistance is in the circuit.I think this is the source of the problem. Am I safe using a wire connected directly to the main 12V buss? It seems to solve my problems, but others suggest this will result in the alternator over charging. I've installed a voltage meter and this does not seem to be the case, but I am concerned. One person suggested that I add an appropriate resistor to mimic the light bulb in the circuit. I am not sure how this would help. The light depends on the alternator providing an offsetting voltage on the circuit to turn it off. This implies the voltage supplied by this circuit will always be close to the alternator output voltage. I checked with the vehicle running and the alternator charging and the voltage on the warning light wire was about 1 volt less than the bus voltage. Thanks in advance for your advice.