In this video i just want to talk to you about this 2006 freightliner M2 "Business Class" model truck. This truck came into the shop, the right front low beam light and all of the turn signals (except front headlight turn signals) were flashing at all times even when the truck was shut off and the key was removed. The only way the driver could get the lights to sop flashing was to remove fuse 17 & 19 which are the CHASSIS CONTROL MODULE fuses.

Now after hours of reading and investigation figuring out theory and operation of this lighting system and wiring circuitry i was able to understand how the system was supposed to function, you see the BULKHEAD MODULE located on the drivers side of the firewall is the main brain of the electrical system and receives a lot of the input signals from the switches and sensors on the truck and then relays those inputs as messages on can network J1939 to other modules which in this case was the CHASSIS CONTROL MODULE. Now as a failsafe design by freightliner engineers they have programmed the software of the BULKHEAD MODULE to control the left low beam headlight bulb and the CHASSIS CONTROL MODULE controls the right low beam headlight bulb in the event that one of the modules were to become inoperable for whatever reason than the driver of the truck would have at least one light in operation during nighttime driving. The issue at hand ended up being a compromised CAN network line between the BULKHEAD MODULE and the CHASSIS MODULE resulting in the right side low beam bulb becoming activated and also almost all of the signal light began to flash.

The area of concern was located at the transmission housing on the drivers side of the truck where the wiring harness runs across from the frame to the transmission housing where the wiring had rubbed through overtime and compromised the wirings insulation.

If you are having this issue check that location, if no damage can be found than you may want to perform a resistance check on the yellow and green network lines that run from both modules, expect to see 0.40 to 0.78 OHM's of resistance. When i inspected the wiring i had found that the green network line was 210.90 OHM's of resistance which is wayyy to much.