I'm planning on installing some Hella FF50 driving lights on the Fit at some point. My plan is to wire them, via relay, into the high beam circuit such that turning on the high beams also triggers the driving lights. Normally this would be simple to tap into one of the high beam wires, but since the Fit uses the high beams as the DRL's, that might trigger the driving light relay all the time (except when low beams are on).

Also, I prefer to keep the DRL's functional.

Does anyone know the voltage that the DRL's run at? Some reduced-voltage high beam systems run the two bulbs in series for DRL, so that would be about 6-7 volts to ground if tapped in the right place. Is that enough voltage that the DRL would trigger the 12V relay used for the high-beam-only driving lights?

I could also track down the relay for the high beams and use the trigger for that relay and use it as the trigger for the driving light relay.

Probably the same circuit as above, but the circuit for the high beam indicator in the instrument panel could be used as the drivng light trigger as well.

Thanks in advance for your input.

 

Many manufacturers use a positive square wave at a key duty cycle to achieve proper DRL intensity instead of a constant voltage of say, 6 to 8 V. This works well on halogen bulbs because a bulb filament reacts too slow to mimic the waveform.

I don't know if Honda uses this circuit in the Fit.

This waveform will look something like this if you scope it.



Your best bet is to find the high beam switch relay and use that as the trigger for the driving lights, because this is a separate relay from the DRL relay.