Aux wiring for trailer (Sedan, 520D)

mike_o · 04-25-2024, 08:42 AM

I've had my garage install a tow bar (AHK) and need to add some simple electrical wiring (didn't trust the shop with that). I have the signals sorted, but I need to physically route the (fairly thin and flexible) cables from the battery compartment to the outside. Prefererable near the tow bar

There are a number of plastic blinds in the compartment, but they seem to lead to nowhere.

I can also route via the rear quarter below the taillight if there's any ventilation openings present.

Any suggestions?

Thanks!

mike_o · 05-01-2024, 01:48 PM

Well, I took it apart and found a 12mm (+-) blanking rubber grommet just below the tail light. The right side one is ideally suited for routing the 4 wires through as they will drop right behind the bumper and reappear next to the tow bar mounting points.

I have made a simple sniffer-circuit that senses brake and turn (l+r) signals and the normal rear light. The CAN BUS has no idea it's there and it will draw current from the free pole located in the battery power distribution box and pass it onto the 4 wires.

04-25-2024, 08:42 AM	#1
mike_o Private 24 Rep 79 Posts Drives: 520d Join Date: Oct 2017 Location: Cph iTrader: (0)	Aux wiring for trailer (Sedan, 520D) I've had my garage install a tow bar (AHK) and need to add some simple electrical wiring (didn't trust the shop with that). I have the signals sorted, but I need to physically route the (fairly thin and flexible) cables from the battery compartment to the outside. Prefererable near the tow bar There are a number of plastic blinds in the compartment, but they seem to lead to nowhere. I can also route via the rear quarter below the taillight if there's any ventilation openings present. Any suggestions? Thanks!
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05-01-2024, 01:48 PM	#2
mike_o Private 24 Rep 79 Posts Drives: 520d Join Date: Oct 2017 Location: Cph iTrader: (0)	Well, I took it apart and found a 12mm (+-) blanking rubber grommet just below the tail light. The right side one is ideally suited for routing the 4 wires through as they will drop right behind the bumper and reappear next to the tow bar mounting points. I have made a simple sniffer-circuit that senses brake and turn (l+r) signals and the normal rear light. The CAN BUS has no idea it's there and it will draw current from the free pole located in the battery power distribution box and pass it onto the 4 wires.
	Appreciate 0 Quote