Multiple trigger wires for auxiliary backup lights (1 Viewer)

[CharlieS]

I'm not sure anyone else is even reading this at this point, but placing this here for future reference when the next person is looking for a reverse wire trigger wire.


I think this EK1 connector one is on the passenger cab side of the firewall right behind that fuse box. The side I can see from inside the vehicle is white, so I presume that is what is meant by the white/blue in the diagram below. I circled the 14 in red on the white EK1 connector for reference. I think pin 19 on this connector is the trigger wire from the brakes.

So if I have this right, pin 19 is the trigger to the tow plug backup light relay, and 14 is the wire that is energized that goes to the backup plug (eventually). I think either could be used in my use case.

 

[LC Mike]

BTW I used these diodes in my trailer reverse light system to prevent feedback to TV and them seem to work great.
15A is overkill, cheap, minimal voltage drop and strong enough leads to just solder in-line on the wires:
15SQ045 Schottky,15amp Diode Axial Schottky Blocking Diodes
like 20 for $6 on Amazon

 

[grinchy]

I'm onboard with your deduction, but I'd actually tap after the relay as that is firewalled from the rest of the system. At worst you bork up the tow lights . . . it does add another failure mode if that stock relay ever gets popped.

On the plugs it looks like the pinouts match, as I think you've decided. They count from 1 to 12 then start over with 13 below 1.

 

[CharlieS]

So this trigger wire works, at least in test mode.

I have a LED test light attached to my switchpro. The pink trigger wire is connected to the blue wire coming out of c3 pin 13.

The test switch is set to disabled on startup. The trigger is setup in the app to energize my test switch when the vehicle goes into reverse. While in reverse, I can toggle the test switch off and it turns off my light. When I shift into gear or Neutral, the LED turns off, as expected.

There is one odd use case...if the vehicle is in reverse (LED on) and I toggle it off, then back on, it stays on when I shift into gear or neutral.

Thinking out loud, I wonder if I can just use this one switch for both purposes (if I just set it to battery, instead of ignition).

Yup, I just tried it. All I had to do was set my existing programmed reverse lights to toggle on with the trigger.