Wipers and headlights share what?

I had a strange thing happen the other day:
I had the lights on and switched the wipers on and the 2 turn signal indicators on the dash lit up and the headlights got a tad brighter. So I tried it again and it worked as normal. So the issue is intermittant, but what circuit do wipers have in common to the headlights? I've looked through the diagrams and I don't see anything that would be causing it.
The headlights are using relays for power but the turn signals aren't.
Could the wiper switch be bleeding power back or not grounded?

Any ideas?
Author: admin