Throttle Dies When Headlights are Turned on

Thought I'd throw this one out there too. 2010 Tundra, 4WD, 110k. A few weeks ago, a few seconds after turning my headlights on, the throttle just stopped working. It was like the engine went right to idle while I was accelerating, enough to be startling.
As soon as I let off the pedal, and gave it gas again, it was back to normal. The next day, turned the lights on again, and a few seconds later the same thing happened. At this point, I started doing it on purpose. I'd turn the lights on, wait for it to happen, let off the gas, get back on the pedal and resume normally. If I turned the lights off, and then on again, it would predictably happen.
I took the truck back to the dealership since I thought this was related to my previous brake actuator issue. They were unable to replicate the dead throttle and told me to bring it back next time it happened.
On my way out of the dealership, I turned on the lights and sure enough, it did it. The Master Tech then came out and rode with me, and I duplicated it about 10 more times with him riding along. The problem was he couldn't feel the loss of response on the pedal that I could, and for about 30 minutes was telling me it was normal, and that the transmission was just shifting and all sorts of other nonsense.
Finally, after I made it happen again, I put the pedal right to the floor instead of letting off it, and nothing happened. Nothing. It should've been smoking the tires at that point, but there was no response. The tech finally said "oh OK, that's a problem" and he took it into the shop. 30 minutes later he came out and we went for a ride again. This time, everything was normal- the throttle was working perfectly!
He told me what he did, and I couldn't believe it. But it makes sense now (I think):
He replaced a taillight that was partially blown. This bulb is the one that has 2 filaments, and sits horizontally in the light housing. One of the filaments lights up when the headlights are turned on, and the other is for when the brakes are applied. At some point, the headlight filament had broken, and had fused itself to the brake light filament.
So every time I turned the lights on, the computer was getting a message that I was braking and accelerating at the same time, and so by default was disabling the throttle. Once I would let off, it would re-enable it and everything was fine.
Moral of the story: even something a small as a light bulb can really screw with things!

 

Sounds like a talented tech. Good on him for finding it so quickly.