Freightliner install information

This is supplement information for Freightliner chassis.

I purchased a wiring harness from Freightliner that leads to cockpit exhaust brake switch.  With the use of continuity checker found the following:
The power supply wire is a White wire and is marked 119C EXH BRAKE SUPPLY
The wire from ECM is a Red wire and is marked N15-C981 EGN RTRDR
Start at switch and follow the harness to a more covenant spot to work on it. Just remove tape wrapped around harness to expose wires. Attach BrakeSwitch wires to these wires.

BrakeSwitch has 6 wires:
2 Red 2 White 1 Purple 1 Black (The color is for identification only)

Cut 119C EXH BRAKE SUPPLY wire, reconnect the circuit by attaching each with a White wire leading to BrakeSwitch control box.
Cut N15-C981 EGN RTRDR wire, reconnect the circuit by attaching each with a Red wire leading to BrakeSwitch control box.

There is a bundle of wires coming up the steering column. It is the bundle going to turn signal. In this group is a red wire with 36E on it. I am told this is a brake light source and can be used to connect to the Purple wire. The black wire goes to GND.

Below is the additional Freightliner
information we have been sending with instructions.

Freightliner Chassis Brake Source

If this does not work, in the cockpit on the forward bulkhead (at base) there are two electronic boxes. The box on left (street side) has the Brake Lamp relays. There is one wire in and two wires out. In most cases the out wires are Red. (One small wire and one heaver in size) When you apply brakes these wires are hot. Connect to the larger of the two wires. The reason for this is: On the Freightliner chassis there is a blocking diode in the brake light circuit that blocks the return power to brake light switch. By going to brake light relay you by-pass this diode. We use the brake light circuit to turn on our relays by applying the brake pedal. The exhaust brake turns on the brake lights and we use this to keep the relays closed.