Search results

I've studied the M939-series wiring diagram and P2P program some more, and it appears that the 12V tap is only used to power the cab heater fan when in low speed mode. I think that a single battery disconnect switch between the negative battery terminals and the chassis should work just fine in...

Interrupting the positive lead, the negative lead, or the between-batteries dogbone will all remove the batteries from the circuit (assuming there's nothing drawing power from the 12V tap at the dogbone cable). A switch in any of those three points would have prevented your accidental welding...

On that topic, I ordered up a few of the Pollak brand keyed disconnect switches that I generally use... and then discovered that my new M923 has loads connected to the 12V point. The M923 has four batteries in a series-parallel configuration. They're only paralleled at the ground and 24V points...

That will work. I think there are potential safety advantages to switching the ground lead, but switching the center connection has the benefit of not needing any changes to the existing + and - leads.

I'll look for some of those Bosch switches to try. The double pole one looks promising for CUCV applications. Thanks!

I don't think that is correct. The switch is not dissipating the full power of the circuit, and in this application it's generally not going to be opened under load. As long as it's rated for use in a 24V system, the current rating should be the same for that service. I've used those before...