Anyone really good with relays? I need a relay that supplies power, except when power applied

Anyone really good with relays? I'm looking for a relay that applys power to a light all the time until you supply power to the trigger line, then the light turns off. Kinda like opposite the way normal relays work.

Idea is, when I switched on one set of lights, I could send the signal to another set of lights to turn them off.

Anyone know which relay I need?

 

@Muddinfun

Would SPDT Relay work here?

 

Standard 5 pin relay but instead of wiring switched circuit to 30 and 87, go to 87a. Run existing trigger circuit to pins 85 and 86.

 

Yep, this.

 

Like this one for example:

https://www.summitracing.com/parts/...MIrLvX6MGc6gIVxsDACh0htgmwEAYYAiABEgJC0PD_BwE

SPDT

30 - 87a is normally closed when deenergized.

 

Just curious, are you doing switch back turn signals?

 

^Yep. Just make sure you don’t end up with a relay that is inadvertently left on for days when the truck isn’t running.

 

Good advice as that will kill a battery quickly.

 

I repaired/rewired a lot of aftermarket accessories on a 1999 Dodge 1500. Ever since I did that the owner claims his battery dies overnight. I discovered last night that the factory blower motor relay is staying on. 1 night of that relay staying on and the battery is completely dead the next morning. It's too early in the diagnosis for me to determine if I made a mistake somewhere or if it isn't related to what I did (I ran out of time and will be back at it tonight).

 

That is why you wire it to an ignition switched circuit when at all possible.

 

Note to self though: The EFI circuit activates intermittently when off because your truck does a self diagnostic test every couple hours.

Installed a buddy's raptor lights for him and every 4 hours or so, his lights will come on for about 5 seconds and switch off again.

 

I didn't say EFI Circuit. An Ignition switched circuit just means a circuit that is only energized when the ignition is on. Like the Stereo, etc ... That way it will not drain the battery when the truck isn't on.

 

Damn that's funny.

 

The EFI fuse IS an ignition switched circuit. It just has a quirk to it. The IGN fuse right next to it would be a better choice since it doesn't get affected by the diagnostic.

Putting that data point out so when people hit it with a multimeter and its cold, but then wonder why their lights, etc flash every so often, they'll know whats up.