Aftermarket LED DRLs

[mp3deviant721]

I wanna know how to wire the LED's to turn off when the fogs are on.



This is how both circuits will be wired. I need the LEDs on when the ignition is on and for them to turn off when the fogs are on, but I don't wanna use anymore switches than I have to. Thanks.

 

[Spott]

Add another relay, so the 12V output of the foglight relay activates it (as well as powering the foglights). Use the NC (normally closed) contacts as a switch in line with the supply voltage from the battery, maybe between the existing DRL relay and the DRL lamps themselves. When the foglights are on, it activates the new relay, opens the NC contacts, and the DRL's go off.

If you want that behavior to be optional, put a switch in the wire between the 12V foglight relay output, and the new relay.

Relays can be powerful friends.

Spott

 

[mp3deviant721]

I was thinking something like you said, with a SPDT relay, I'd put the wire leading from the fog switch to terminal 85 and ground 86. Then run battery power to terminal 30 and have 87a connected to terminal 30 of the relay for the running lights which would have a 4 terminal relay. Then have the fogs connected to terminal 87 on the SPDT relay. That should work, right? I found a relay that should work, it is the same relay that our trucks use for the fuel pump. It's a BWD relay that I'm going to get, #R3177.

Edit:

I shouldn't have to ground the SPDT relay which controls both circuits, right? Just run it in series with the wire coming from the fog light switch should work, shouldn't it? That would save me some work in finding another ground.

 

[RangerSVT]

85 to ground, 86 to fog light switch power (or fog light), 30 gets ignition power, 87A goes to DRL...When ignition is turned on power goes to DRL, when fog light is on, activates relay breaking contact between DRL and power, thereby turning them off
SVT

 

[Spott]

Yes, you need a ground on the other leg of the control coil of the relay. #85 or 86, I guess. The relay coil needs to see 12V across it, or it wont activate.

If you tried to run the fog lights THROUGH the coil, you'ld fry the coil immediately, and then your fog lights wouldn't work.

Spott