Light Switch

[Red_506]

I have installed a lighted license plate holder, and am trying to get it to power up only when I turn on my headlights. I know I can simply cut into the rear running lights, but I'm trying to avoid that. I want to go directly into the headlight switch, but I am unable to find a wiring diagram to show me which wire is actually hot when the headlights are on.

If anyone has either the wiring diagram or knows which wire to splice into I would be very appreciative. Thanks.

 

[pigfoot63]

Brown wire in tail ligth wiring harness

 

[Red_506]

Would that wire make its way all the way forward to the light switch? I have already run my wiring to the front of the vehicle as I did it in conjunction with another set of wires for an accessory power port in the rear of the truck; however I have constant power with a local switch for the accessory port and want the license plate only to light up when I have the running lights on.

 

[Warthog]

Have you downloaded the free tech manuals? The wiring diagrams are in the appendix of the -20 and -34 manuals

 

[Red_506]

I have, but have not seen any diagram specifically related to the light switch.

 

[Warthog]

You won't find it. You have to decipher the wiring to find the correct wires. It's like connecting the dots

 

[Red_506]

Fun

 

[Warthog]

If you look at diagram E-14 from the -34 manual, you will see that the "park light" wire is ".8 BRN 9A" It is connected to pin #4 of the headlight switch.

I'm sure you have read the first few pages of the Troubleshooting Section to learn how to read the diagrams and know what the wire labels mean.

Ignore the red circles. They are the diodes on the flashers. Another project.

 

[Red_506]

Thanks alot, the brown wire was it. I now have a working license plate light that only turns on when my lights are on.