adding auto on aux backup lights to switched lights

I have 2 separate sets of aux lights wired per attached. One set is auto on with reverse, one set is switched. If I wanted the auto on one to be controlled by switch and still be auto on, could I splice into the "switch to 86" wire and run into the 86 on the auto on relay? Would I need a diode on the "reverse to 86" wire?

 

@RainMan_PNW is one of our smart wiring guys.

 

https://youtu.be/hjpucoy0Qxo

 

It depends a little bit on what your reverse circuit is rated for and what your aux lights have for a draw, and what you want the final function to be.
In theory, you could tap the switch into the coil signal on your current relay and add a diode to the reverse signal (to prevent your reverse lights from coming on). It's potentially a little messy, but a possibility - I don't have a lot of experience with using diodes and I tend to like positive discontinuity where I can use it.

The simplest method would be replacing your switch with a SPDT switch like he shows in the video above, and then running all of the lights off one or the other using a single relay - but that would require all of your aux lights to work in reverse (in order to use a single switch at least).

Another method would be to add a new SPDT relay in front of the coil on your two aux lights. Run the reverse circuit signal to 87a (normally closed). Run signal from your switch to BOTH 86 and 87 (86 to power the relay on when you turn on the switch, and 87 to provide power to the relay circuit itself). Then, run a wire from pin 30 to pin 86 on your existing relay. Essentially, this is providing to separate "power" sources (87 and 87a) to a single common outlet (30). When the switch is OFF, the SPDT relay will close on pin 87a and that will feed the reverse circuit power through the first relay and on to 86 of the second relay (which is then triggering the coil for your aux lights). When the switch is ON, power from the switch triggers the SPDT coil (pin 86) and powers through the relay (pin 87) to then trigger the original coil again.

Hope that makes sense. I can try scratching out a diagram if it would help.