Reverse lights stayed on, now nothing
 

Anyone know anything about troubleshooting reverse lights?

2004 Audi A4 B6 3.0 Quattro (with Tiptronic... I think)

The wifey came home last Tuesday and I noticed that they were on, and had been since she left work. One side burned the housing (didn't think my 100 watt reverse lights WOULDN'T melt through stuff though), and the other side had already gone out for some reason.

Fuses are good, and while the lights don't come on, each side reads 8-10 volts when the car is in reverse, and nothing when the car is in any other position. The ground isn't the issue, as they still don't come on even when I do a direct ground connection to the chassis.

I'm thinking it's the reverse switch, but I can't figure out if it's to the Passenger side of the tranny by the CV joint, or in the inaccessible abyss on the top of the tranny.
I'm not sure what controls the passenger mirror tilting downward in the reverse position, but that still works. Vag-Can electronics scan shows that they're getting an "ON" signal to light up when they're supposed to, but I can't figure out how to tell if the switch is being activated.

I'm really hoping that it's not an Electronics Module, and really not looking forward to a $90 diagnostic fee. Hell, for $10 I could mount a pressure switch at the shifter... WHERE IT SHOULD BE.

Any Ideas?