Lights on, Truck stalls
 

Hey people, The other night I my 4.9 Inline 6 cyl. f150 sputtered briefly, well basically died and restarted while driving. It did this a few times, then just quit running.

I pulled off the road, turned everything off (A/C, radio, lights) turned the key and it started right up. As soon as I turned on the headlights it died again.

So i drove home without lights, next morning swapped out the alternator, as I assumed it was the issue. (And when I put a multimeter to the alt/volt reg. it was reading 17+ charging volts).

Last night only drive home (with the brand new alternator in it, same problem.

Only this time I was very far from home and the drive without lights almost cost me a ticket.

Any input??
Aside from "Don't drive without your lights on" ;)

More info
 

OK, so I took the truck to the local shop where he confirmed that when I turn on my headlights the truck dies.
He then disconnected the right headlight bulb and the truck wouldn't even start!

Also, I noticed that when the truck is running the right headlight bulb has a very low glow to it, as if getting a small amount of electricity even with the light switch off. As well as the right turn signal indicator on the dash.

Any ideas where the problem is with this?? I assume a short, but how do I track it down?

Without the engine running the lights come on just fine.