I measured it once, kept reading about how OEM wiring was under spec'ed and led to voltage drop at the headlight, so I measured the voltage + current, and got a bit over the 55W rating for the regular headlight.

After the first measurement I thought I proved that the wiring was seriously undervolting the headlights when I only measured around 10V (and just under 40W), then I realized that was the DRL's.

To find the 3W spec for the LED DRLs on my current car, I just looked up the specs on an replacement module - I don't crawl around the hood with a multimeter anymore, too much expensive stuff in the way.

(the reason I measured in the first place was because I wanted brighter headlights since I was doing a lot of night driving in mountain roads, and thought that replacing the wiring harness would be an easy upgrade. I ended up adding a set of driving lights which looked kind of dorky, but worked great)