What device will allow 12v but not 9v?

[paulmackie]

I just fitted HID lights to my car, the DRL circuit is putting out 9 volts, which is bringing on the high beam of my headlights (the DRLs used to activate my high beam headlight at a reduced voltage of 9 volts-now the 9 volts activates the high beam HID relay).

What I would like to do is stop the 9 volts going to the high beam headlights and tap off the wiring before whatever is stopping the 9 volts with a relay that will bring on my fog lights as the DRLs and allow 12 volts to pass when I need headlight high beams.

As far as I know, here in Canada DRLs have to be on by law.
The DRLs come on automatically when the car is put into drive.
Basically I just need the headlights to come on low beam instead of the DRLs high beam, or stop the voltage going to the high beam and wire in a relay that brings on the fogs as the DRLs.

Thanks for any help with this

 

[Arouse1973]

If you disconnected the DRL limiter would you still have main beam? Or is the limiter bypassed when you put your main beam on. If so then could you disconnect the DRL power, connect you main beam wiring to the HID main beam relay and connect another relay to the DRL power to power your fog lights?

You may have to put a large diode in series from your original fog light wiring to prevent feedback to any fog light circuitry that may get damaged, but this is most likely isolated when the fog light switch is not on.

Also it is good practice to put a diode across the relay coil to prevent back EMF going up any cable and interfering with your car electronics. You connect the cathode to +V of the relay and the anode to the negative (0V) of the relay power.

Have a look on the net, there should be lots of info on here about connecting up.
Let me know what relay you want to use and I will tell you what diode you need. You can't put just any diode across the relay.
Thanks
Adam

 

[jcurrie]

in factory DRL there is a relay activated buy a LDR / photo transistor that switches between DRL and regular lighting.
jc

 

[paulmackie]

Hi,
I have a Jeep Patriot 2011, the 9 volts comes from a circuit board and goes straight to the high beam, which is a dimmed light for the DRLs (Daytime Running Lights), when the high beam is activated it puts 12 volts in the same circuit shown in the diagram; the low beam is activated by a separate circuit board, so there is no limiter, just reduced voltage for the DRLs.

The HID harness is plugged into the connector going to the headlights and has a solenoid in the HID projector that operates the high beam and operates with the reduced 9 volts; when the car is put in drive the high beams (DRLs) come on, which even during the daytime are blinding for other drivers.

What I am looking for is some way to restrict the 9 volts going directly to the high beam wire (white/pink, which operates the HID harness solenoid turning on the high beams) and effectively turn off the DRLs, but allow 12 volts if I need to use high beams.

If I could stop the 9 volts and allow 12 volts I would then add a relay using the 9 volts and turn on my fogs, which would replace the DRLs.

Thanks.