I'd like to wire my camper shell so the interior camper dome lamps turn on when the truck cabin lamps come on (like when I unlock the doors) AND when I turn on the cargo lamp light.

IIRC the cargo lamp has two positive circuits, one of which one is grounded negative when you turn on the lamp.

Do the interior lamps do this as well? Will this be a simple "diode" type connection, or will this be a little more involved?

How can I make this work?

I was thinking that running a positive source to the dome light, then splitting the "ground" wire to both of the "ground" wires of the truck cabin circuits with diodes so that the cargo lamp doesn't turn on the interior truck cabin lights, and the interior truck cabin lights doesn't turn on the cargo lamp.

The thing is I know a diode will permit + one direction but not the other. I don't know if it will allow - to go only one direction.

example: + > [diode>] + is OK
+ > [<diode] + is not OK
but is - > [diode>] - ok?
or is - > [<diode] - ok?

Did I explain that right? And will it work?:confused:

Thanks

JT

Diodes will work either way. Whatever potential is higher will flow through the diode. If it is a negative trigger, then turn the diode around and it will work the same as a positive trigger with the diode the other direction. . .

Great, hopefully my idea will work as I plan.

Thanks

JT

To provide a little more protection and separation, I would use a relay to supply the camper lights, maybe from the aux batt circuit in the camper harness/trailer harness, and trigger it via forward-facing diodes from both the cargo lamp and interior lamp circuits. I didn't look at the book- if they're both ground-triggered, then the diodes would be reverse-faced.