Help find 12v illumination wire

[CornM3]

Hey there, I’m trying to find a 12v wire that only activates when the parking/headlights turn on. It’s for an aftermarket gauge.
Anyone know which wire it is? I tried all the wires behind the headlight switch but none of those worked surprisingly, they actually dropped voltage when I switched it on lol
Please if anyone knows please let me know.
Thank you!

[Yoko22R]

Curious to know what kind of gauge you are wiring up that you'd want it powered only when the headlights are on.

[CornM3]

Originally Posted by Yoko22R

Curious to know what kind of gauge you are wiring up that you'd want it powered only when the headlights are on.

Aftermarket boost and oil temp gauge, it needs a “12v dash light wire” for the light inside the gauge so it’s not always on just at night when I turn headlights on.

[Yoko22R]

Originally Posted by CornM3

Aftermarket boost and oil temp gauge, it needs a “12v dash light wire” for the light inside the gauge so it’s not always on just at night when I turn headlights on.

Got it. I'd just take a multimeter to all the fuses and click the headlight switch on and off until I find a fuse that is consistent with the switching of the headlights.

If that doesn't work, might have to t-tap off of the load side of the headlight switch.

[CornM3]

Originally Posted by Yoko22R

Got it. I'd just take a multimeter to all the fuses and click the headlight switch on and off until I find a fuse that is consistent with the switching of the headlights.

If that doesn't work, might have to t-tap off of the load side of the headlight switch.

Yea I was gunna try the fuses, as that’s what I did for the actual 12v to power the gauge (without lighting) just didn’t want to run another long wire across lol but which wire would it be behind the switch? When I tried them none of them worked or as stated the power would actually go down when using the switch.

[CornM3]

I can’t locate the fuse that activates with headlights, anyone might know or maybe I’m missing something?

[jdamore]

I don't know exactly an easy wire you can use but if no one chimes in, maybe this will help. If you are electrically inclined and have a meter, you could test and try to find a wire going to the light switch module or the hazard button module. In other words, there is a "dash light" wire that powers the led lights in those modules.

I attached two photos. One for each of the modules. Use these as a map to the pins that COULD be carrying a 12v signal for the lights. I indicated what I believe is the correct pin based on the traces on the pcb (keeping in mind that this is the front of the module and the wires will be coming out the back). Put your meter to the chassis (black) and the pin/wire (red) and check the actual voltage.

Hope that helps or at least steers you in the right direction.

FYI-
The fuses are before the light relay so that wont work.
There is no "load side" of the light switch. The switch is just sending a signal to the FRM module.

[CornM3]

Originally Posted by jdamore

I don't know exactly an easy wire you can use but if no one chimes in, maybe this will help. If you are electrically inclined and have a meter, you could test and try to find a wire going to the light switch module or the hazard button module. In other words, there is a "dash light" wire that powers the led lights in those modules.

I attached two photos. One for each of the modules. Use these as a map to the pins that COULD be carrying a 12v signal for the lights. I indicated what I believe is the correct pin based on the traces on the pcb (keeping in mind that this is the front of the module and the wires will be coming out the back). Put your meter to the chassis (black) and the pin/wire (red) and check the actual voltage.

Hope that helps or at least steers you in the right direction.

FYI-
The fuses are before the light relay so that wont work.
There is no "load side" of the light switch. The switch is just sending a signal to the FRM module.

Hey thanks man! Yea I’ll definitely look into that this weekend. Hopefully I don’t mess anything up lol