Which wire to use? DRL question.

I have an '09 W/ DRL's. I want to eliminate the factory torches and add an LED strip somewhere.
I have the two wire set up, which one is for the DRL?
(And where's the ground wire?)
Or should I tap into the G/R at the relay?
THX

PS. I couldn't find info via search button, but if it's out there, I'd appreciate the link.

 

OK, I pulled the grill and got in there.
White w/ black is the DRL.

So if I cut that wire and spice into the hot side for the new lights should I ground the (original) bulb side so the flashers still work?
I'm just a tad confused as there is no ground to the 4157 on this truck.
Don't want to fry anything.

 

Sometimes it just helps me to write stuff down.
The white and black is the ground.
I'm gonna have to jump off the G/R at the relay.
New question, doe the G/R come through the firewall?
To access under the hood.