Question about extra wire at trailer hitch

[Stew Tabak]

Greetings from stormy Northern CA: I’m a newbie with a ‘23 DX3 34KD. Towing a pickup truck that’s equipped with a BrakeMaster system and so had the coach plumbed with an airline for the tow vehicle brakes, which works fine. But I want to add the Roadmaster indicator light on the coach dash which lights up when the tow vehicle’s brakes are activated — I like that reassurance and visual reminder. Does anyone know if there is a ”spare”/extra wire in the loom at the rear of the coach that I can use for this rather than having to run a new/separate dedicated wire from stem to stern? Thanks much for any guidance.

 

[widdershins]

I think my first choice would be to use the reverse light wire on the 7-pin. Second option IF you don't have or need a brake controller would be the electric brake line, however IMO that could be useful in the future.