Yes, it's supposed to be on the Driver's Side catch - it's a small microswitch operated via that catch mechanism.... Perhaps it was broken and someone changed it for the type on the other side (without switch) and 'fudged' it ? There is (normally...) a two-wire waterproof-type connector located about 4 inches below that switch.... ( Don't think it is the cause of your drain though but you never know... )