I noticed yesterday that my radio display goes dark whenever I turn on the headlights. I have the Putco relay system hooked up to the headlights to minimize the draw through the headlight switch. I have no clue about wiring or how to read those diagrams. How can the headlight switch affect the radio display?

 

Radio display dims with the dash lights. Headlight switch controls that. If you twist the ****, does the radio display get brighter?

 

I forgot to mention I tried the dimmer. It works with the headlights off. But once I tun on the headlights there is no lighted display on the radio. The head unit, am/fm/cd/tape is from a newer truck.

 

New "thing". I do not drive in the dark much so it never occurred to me to check. The other morning I had to drive when it was still dark and I notice there is no change in my headlights when I hit the high beam. The light in the dash comes on but the headlights do not change. ?? Is this because of the Putco relay system or would it be something else?

 

Only if the relay system isn't wired properly.