Here's the XC chassis installation.
We installed the Brake Switch in our Journey which is built on the Freightliner XC chassis. The Brake Switch is designed to change the way the exhaust brake operates by allowing it to trigger on by an application of the footbrake, rather than by the releasing of the brake pedal.
The Brake Switch is a small plastic box with 6 wires: 2 White, 2 Red, 1 Purple, and 1 Black. Adequate wire length is provided to allow ease of connections and the securing of the box in a convenient location. Once wired in, it is not necessary to access the box so it may be completely hidden behind the dash.
On my Journey, the first step is to remove the rear dash cover to allow access the wiring connected to the exhaust brake switch. Once the switch is accessible, I found it easiest to unplug the connector from the switch to allow easier splicing of the wires. You may need to remove the electrical tape and some of the black wiring loom covering the wires to see the identification marks on the wires.
Looking at the exhaust brake connector you will see 6 wires coming from the connector. Identify the wire marked with "119C Exhaust Brake Supply". This wire is to be cut, and the two white wires from the Brake Switch spliced into the cut wires.
Next, identify the wire labeled N15-C981 EGN RTRDR and cut it. The two cut ends are spliced to the two red wires from the Brake Switch box.
The photo shows my connections to the wiring harness where it attaches to the exhaust brake switch connector.
After splicing the wires at the switch, you can re-attach the exhaust brake switch connector to the exhaust brake switch as you are done with those connections.
The black wire from the Brake Switch box is connected to any convenient ground connection. I actually crimped a ring terminal to the black wire then connected it to an existing ground screw located behind the dash.
The purple wire is connected to a brake lamp signal source. This connection does take a bit of care to get correct. What you need to do is locate a brake lamp connection that receives power both from the brake pedal and from the exhaust brake application. The brake light signal we need can be picked up from the brake lamp relay like we did on the Vectra chassis or from wire 36E or 36H in the Freightliner wiring loom. In my case I knew that the brake signal I needed would be present at the brake lamp diodes under the dash so I made the connection there.
In the photo below, you can see the brake lamp diodes. It may be necessary to cut several wire ties that hold the diodes in place in order to free them enough to read the wiring labels. There are red wires connected via faston terminals to both ends of the diodes. Wire 36H is a red wire connected to one end of the diodes and provides the necessary brake lamp signal. Connect the purple wire from the Brake Switch to wire 36H .
Finally after all the connections are made, I refastened all the wiring with wire ties to keep the wiring orderly and put the dash back together.
The trip home with the Brake Switch was a much more enjoyable drive as I wasn't constantly reaching for my exhaust brake switch and also didn't have the unexpected application of the brake when I was wishing to coast.
Adding the Brake Switch is a great mod!