Help with Retrofitting DRLs in Suzuki Swift MK3

[SwiftTraveler]

I’m retrofitting DRLs into my Suzuki Swift MK3 using fog lights. I’ve tested it, and it works, but I’m stucks on how to dim the DRLs when the headlights turn on. I conected the DRL kit to the 12V power wire for the headlights, but the voltage reads 12V even when the car is off, meaning the DRLs stay at half brightness

Any ideas on how to signal the DRLs to dim when the headlights are on? Appreciate any help