I am installing a digital led voltmeter gauge. The instructions call for a ground, a keyed hot and a third wire to the "headlight circuit"? to dim the LED's when the headlights are turned on. It says not to connect it to the dash light rheostat control wire or the dimming feature will not work right.

So, what would be a example of a good headlight circuit wire to tap into?

 

A brown wire that feeds your overhead cab lights if you have any. On the older trucks it was over in the driver's side kickpanel area with a empty plug if you didn't have that option. All of the running light circuit is a brown wire, but most of them are outside the cab. You may also be able to find it at the fuse box if you have a towing package. You may have a towing lights relay. If I remember right the towing lights wire is brown with a white stripe.

Or if you want to think about it for awhile, just hook it up without hooking that wire up. If the display is too bright at night, then you will have to do something, but maybe it won't be too bad.

 

Brown wire behind the headlight switch worked great .

Thanks