I really liked this book because I really like horses and I like how the horse has to jump wire fences and doesn't get scared and had to jump big rivers. (goodreads.com)
-- if that is the case you could simply jump a wire across the connections on each switch, in turn, to bypass the switch and confirm whether it is the problem. (mechanics.stackexchange.com)
Trailering Package, heavy - duty includes trailering hitch platform, 7 - wire harness (harness includes wires for: park lamps, backup lamps, right turn, left turn, electric brake lead, battery and ground) with independent fused trailering circuits mated to a 7 - way sealed connector and instrument panel jumper wiring harness for electric trailer brake controller (orangecoastautogroup.com)