Occasionally, not all the time, I will hear a rather loud "tick, tick, tick" coming from appears to be from somewhere under the rear seat of my '70 beetle. The sound stops when I turn on the headlights. Any idea where the ticking sound is coming from, and why? Thanks, Ed

 

There are relays under the rear seat, just lift the seat and see whats under there, also there are other wires there as well, you might have a loose conection or a short arcing.