I've had the same setup in my 2001 ford ranger (work truck)
Ford runs their DRL on the low beam of the headlight at a lesser power than the 12-14 volts the car runs on. It's more than 9 volts though for sure. I saw a post suggesting 10.
Can-Bus Ballasts
I truly believe these are the best ballasts you can get for cheap. My jetta used to eat ballasts (a set every 8 months). The canbus ballasts have been going 3 years on that til when I sold it.
now, more importantly. These ballasts run on as little as 9Volts. That's all they need to fire up.
I have slim Can-bus ballasts on my 2013 edge rated for 9-16 volts. Direct plug and play with no relay harness. Everything works like it does from the factory. Even the auto switch. I have the same setup on the ranger and the DRL fires both as the HID.
They also have error cancellers so you don't have to worry about bulb out warnings.
The bulbs I had, needed one prong trimmed. Took 5 seconds with a snip. No big deal. Save yourselves the headaches of having extra relay and wiring parts. The canbus ballasts work great for fords
