YES you CAN turn off DTRL w/ engine running, here's how:

I searched the forums for this so sorry if it is here somewhere, but I just discovered (by accident) how to turn my Daytime Running Lights off with the engine running. (On my 2012 DCSB V6 Prerunner.)

With no mods, no wires, and no switches added or wires cut. The reason I wanted to is first of all I hate machines doing things for me or telling me what to do. Secondly there are times I want the truck running but not the bright amber lights glaring. (Like if I am waiting in a Miami parking garage at 2am when it is 93 degrees out, and I want the engine and AC on, but don't want to advertise to every carjacker in town that I am in my Tacoma with the keys in it).

So, no this doesn't work when you are driving, and I am all for safety, so I am fine with the DTRLs on while on the road. But YES, you can disable them while parked with the engine on. Here is how:

Do these steps in this order:
Park. (Put vehicle in "Park".) Turn engine off. Remove key from ignition. Depress Parking Brake. Reinsert Key. Start Engine.

Whala! The Tacoma is running, but no bright lights are on. Release the parking brake, and your extra safe DTRL's are back on.

I think most people looking to "disable" their DTRLs or add a switch to turn them manually on and off just want to do so for the same "parking with the engine on and not advertising it" reason, so feel free to link any posts you see about that here. And if 100 threads already figured this out I'll take this down, but I couldn't find them.

Rock On!