Auxiliary backup lights relay question

I picked up a set of Rigid SR-Q backup lights (kit version). By default, these lights have a 3 position switch on/off/on with reverse lights.

I would like to wire in a second relay so that in position #3 the lights only come on with my headlights/taillights. Can someone explain what type of relay I would need and how to wire it in layman's terms? TIA

 

[drdoom]

You could put an add-on relay to the power wire under the hood, and get the trigger voltage by tapping into the headlight bulb connector. Use an LED test light to find the right wire. The LED light that shows ground and positive are good for that.

 

[DsN]

Sorry, to clarify ...

Position #1 : Manual On
Position #2 : Off
Position #3 : On w/ reverse

I would like to add a relay so position #3 is instead "On w/ reverse and headlights/tailights."

 

[drdoom]

Sorry, then use the add on relay to control wire 3A again triggering off the headlight connector harness. Probably an better way to tap off the switch if someone knows how.

 

[DsN]

OK, thanks. That's what I was thinking, but wanted to confirm due to my lack of electrical knowledge. Since I'm already tapping the reverse lights with 3A, I'll probably just tap the taillights with the second relay.