pre-horn relay, one horn terminal is to power the other is to the horn button, which supplies the ground, correct connection [not "polarity" really] avoids current thru the column, reversing the connections causes the path in the column to carry full operating current, not a good thing

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics