Many issues t660

BCM = Body Control Module.

These trucks are CANbus, which means instead of having a set of wires (+ and -) going to every single switch or component and the switch controlling the circuit, there’s only a pair of main network cables running throughout the truck with subharnesses going to each switch or component. Instead of it being basic voltage running through the wires and the switch turns the circuit on/off, CANbus is transporting a packet of info through these cables, to the BCM, which tells the different components what to do. It’s why when we hit the door lock switch or window switch, there’s a delay in the action we’ve requested. It’s not a switch activating a component; it’s a button that triggers an info packet, requesting the BCM to activate what we want. It’s a highly sensitive and very complex system where any minor hiccup in voltage, connectivity, etc, will render it useless. The BCM controls everything within the cab. If it’s faulty, usually, the systems within the cab will experience random failures. If you think of the BCM as the brain and the brain is faulty/crazy, there’s no telling what the rest is going to do. Again, it takes replacing it as a trial-and-error. If there’s no more silliness going on after the replacement, the BCM was the issue. If it doesn’t fix it, the new BCM will need removed and a very intelligent tech will have to spend a lot of time going through the network. Unfortunately, the trucking industry is such a joke that no one in the industry cares all that much about the driver enduring the BS, so the time and money isn’t going to get spent on a repair, warranty or not.