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Was reading about using a relay for headlights..the person used two relays, one for low beams, and one for high beams, won.t a dpdt relay work?..
The idea is to get all the heavy lamp current out of the headlight and dimmer switch. Less stress on switches and less voltage drop to lamps.
Using a DPDT relay, fused but contacts fed directly from power source as relays typically are wired would mean that the beam on the normally closed contact would be on even when lights are supposed to be off.
The typical setup has the relay commons wired to power with the N.O. contacts to the beams. That way neither beam is powered unless commanded. The headlight switch then only has to power a few milliamps to the coils thru the dimmer switch. That switch selects the appropriate relay to carry the 10-15 amp current. When headlight switch is off, neither relay is on so no lights.
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