On a 71 cutlass, the grid type defroster gets its "main" power from the horn relay + post. The "activation"/ switch power comes from the voltage regulator so the grid is not on unless the car is running. However, a 71 442 uses an internally regulated alternator with no voltage regulator. Does anyone know where the "activation"/ switch power comes from on a 442. This is for an A/C car with the three-relay system. The only wiring diagrams I can find in my manuals are for cars with voltage regulators.