Here’s something I’ve learned about truck electrical systems, as something that is very important to the reliability of the truck itself not enough attention is paid to the batteries themself
The batteries are the power source for all the electrical sytems on the vehicle, with the amount of sensors and suchlike that can shut a truck down, it makes sense to have the batteries at full power all the time, a fluctuation of a fraction of a volt can trip out a sensor and cause no end of problems. So starting at the battery terminals, check all the electrical connections for integrity and waterproofness (is that a word) and it’s very important to check all the earth connections and make sure everyting is in good shape there and it will minimise the problems from voltage drop and may contribute to troublefree motoring
Thats what you get if you put a computer in charge.Something as simple as opening a window has to go through a “protocol” before the processor in the door can trigger the window motor.
Each signal from the switches are “prioritised” .The signal is sent to an ECU which is connected to all the other ECUs (Actros has 8 or 9) If one of these ECUs has a higher priority signal than the other,that signal is put into a queue.
Thats why when you turn on the headlights they usually take a second or two to come on,
all the other ECUs have to be “consulted” and checked that there are no “protocol 1” signals that have a higher protocol number.
This system was designed for aircraft to save weight.Only one power wire to each ECU instead of power from each switch and you could mount the ecu near what they were controlling eg window ecu in the door controls window,mirror heat and position,central locking etc.Sometimes the digital signal goes astray and this puts up a fault message on the dash.Only thing you can do is wipe the ECU memory to clear the “fault” that never really existed. A bloody nightmare but good on paper.
