I switch it off when ever my trucks are parked (good against surface leakage when parked for a while - no empty battery) & it`s a theft protection too.
Involves all wiring .
Mounted on the dash (the RED) near steering (right side) and on the little edge of the dash right to the steering wheel ( BJ43 *)
Cheers
Peter
* BJ43 part is for 24 V
...drove the RED today and made a pic....
