2002 T800 I'm looking to add: - Amps - Front diff/rear diff/transmission temps How do I hook up the sensors for these? Putting in the gauges is easy enough (thank you Kenworth!), but the sensors are another thing. I found leads under the dash for the front diff/rear diff/transmission temps but I can't seem to find them where the harness would plug in at the frame. So I'll probably just run new wires. How are the grounds done on the diffs? Do I somehow ground to the sensor? If not, how? I noticed I can do the rear diff fairly easily, as the leveling valve has extra holes. The transmission shouldn't need a ground. With the amps, how does that work? I know old school amp meters literally took the hot line from the alt to batteries and spliced into it. I don't think that's a good option. One terminal says "alt" and another says "batt". Somehow I don't see 150+ amps going through those itty bitty terminals, so I'm guessing it's a parallel rather than series hookup.
The single post temp sensors ground through their body so only a single wire from gauge to sensor would be required. The amp gauge would use a shunt which the gauge taps in off so the heavy wiring doesn't go into the cab, this can be installed on the firewall bracket if your starter relay and 135 amp breaker are located there, otherwise it would go in the battery box.
Get ahold of your KW dealer, from my understanding you should have most everything harness related that you will need already there. You just have to find it, or at worst get a jumper from the harness to the sensor you want. Are the senors already in place, or is there plugs?