Backup lights, wipers, switch

You may have a 2-speed wiper. Mine (67) is 2-speed and has 3 wires also.

I love that wiring diagram!

I see the power goes thru wiper switch "B" and thru internal circuit breaker and out thru B/U backup lamps switch. I read this on another post with pics of the switch so credit is not mine.

You may have to take your switch apart and clean the contacts.

On edit that clicking sound could be the internal circuit breaker....


Oh here is a Part# on mine: