Okay on New Year's Eve, I drove about 200 miles. As I was getting off the exit ramp, I used my right turn-signal & the headlights blinked. Thought that was kind of weird; proceeded to make another right turn, and noticed the headlights blinked again when I used the turn-signal. A few hours later, was getting ready to drive back home, but the headlights didn't seem to be working. Checked all fuses & lightbulbs. Figured problem was in the switch. High-beams worked if kept in "pass" mode. (Only) tail lights seemed to work if light switch was on. I have a 1998 A4, B5 FWD tip. 1.8T. Also noted that transmission display was in limp home mode. After returning home, removed switch (saw it was melted down). Would the melted-down light switch have any affect/correlation with the TCM?

 

Do you have tip switches on your steering wheel? If so, other steering wheel electronics may have been affected by the melted switch. After you replaced the switch, what happened?