Hi all,

I am trying to install my new rear bumper mounted backup lights to run off both my Bosch relay with a switch in the cab and from the backup lights. The system is currently running off only the switch, as I have had a bit of difficulty in finding the correct backup light wire.

Can anyone here verify which of the two wires I have at my backup light bulb in the taillight is the correct trip wire for the relay...I have a gray with light brown in the center of the bulb socket and a black with green on the outer side of the bulb socket. I am guessing the gray is correct, since the same black with green wire is on all of the other taillight bulbs..and thus might be a ground...

I would be wiring the relay posts as follows:

30: 12v (15 amp fused) in directly from battery + (and power to switch fused @ 3amps)
85: Ground to vehicle body
86: ***whatever the correct factory B/U light trip wire***
87: Positive to the mounted backup lights
87A: Power on from interior switch

Anyway, thanks in advance for any advice.

JJ