Kill switches on Freightliner Cascadia?

Easy. Just buy a high amperage rated master disconnect switch and install it between battery negative and the truck frame.

 

Something similar to this.
Battery Master Switch 75910 DPST On/Off – Cole Hersee

 

Its been done the way I described for decades.

 

Pretty much. I used truck frame simply because that's where the battery group is usually grounded. I'd stick with using whatever location your truck already uses for a ground and just put the switch between there and the battery.

I've also been told that if the ECM is connected directly to the battery terminals that they should be relocated to the other side of the disconnect switch so that the ECM gets disconnected as well. Apparently if you accidently try and crank the engine with the switch off it could cause the ECM to get spiked if its not been isolated.

 

The newer freightliners and Western Stars don't actually kill power to the truck by opening the ground, they just shut down the PNDB, which in turn pulls the power from the other power modules.

Personally, I like the method @AModelCat suggests. You know everything is dead when there's no ground to the battery.

 

men what you want? part numbers of kill switch, pndb and wiring harness?