12 volt power to toad lights

[brandysdad]

I mentioned to a friend that I was going to install diodes into my Ford Edge tail lights and he asked an interesting question.
What happens when you activate the brakes in the RV and send 12 volts to the toad brake lights, and your toad braking system pushes on the brake pedal sending 12 volts to the same light. Are you feeding the toad lights from both the RV and the toad batteries simultaneously? It is my understanding that diodes limit the power to flow only to the lights and prevent back-feeding between systems. Are we now feeding 12 or 24 volts to the lights? Or are the two vehicles working in parallel?
I didn't have an answer.

[Robbbyr]

The two feeds would work in parallel, and as a result the bulbs would only receive 12-volts. And the bulbs will use the same amount of current as they would with a single feed, no danger of them using more current and potentially being "too bright".

I have a 2014 Explorer which uses LED tail and brake lights also, and wired them for towing with Roadmaster diodes. No problems at all in the two+ years I have drug it around. And there are times the lights are being fed from both systems without issue.

[brandysdad]

Thanks Rob, that's what I thought.