So recently the relay went faulty on my SW Motech Evo fog/running lights. I bought the LED lights with integral relay switch and wiring loom for my twin cam GS back in 2014 and since then transferred them to both LC GS’s. The relay was firing off the back of the accessory socket on the LC GS’s, this is at the front of the bike near the TFT and since the bike was under warranty meant I couldn’t get the relay positioned under the seat without cutting into the bikes wiring loom. Instead, back then I opted to tuck the relay under the ‘beak’ and use a clamp connector on the nearby accessory socket.
Unfortunately, despite going to great lengths to wrap the relay in plastic some water still penetrated over time and the relay developed a current leak that drained the battery. A cheap fix would have been to rewire the light loom and replace with a new relay, but it still meant I had to cut into the bikes CanBUS system somewhere and risk invalidating the warranty. The most expensive solution for this would be to just go out and buy the BMW OEM fog lights and replace everything, but at £500 fitted by the dealer and knowing my lights worked perfectly well I started looking at other alternatives that allowed me to reuse the Evo lights and keep the Denali aftermarket light bar mount too.
The solution I chose in the end was to buy the Hex ezCAN device from Nippy Normans (£160). This small water resistant device not much bigger than an old style USB pen drive has four 10A output circuits designed for a variety of accessories and couples into the bikes CanBUS system without the need to cut cables and invalidate the bikes warranty. On the GS the coupling is via the RDC unit .. the Tyre pressure monitoring system under the pillion seat. Basically, you plug the ezCAN into the RDC unit and the original RDC plug connects to the ezCAN putting the device in series. Therefore, the CanBUS system has now been extended. You use software loaded onto a laptop to plug in via a micro USB connection to control and set each of the circuits to include the software ‘fuse’ ratings. By calculating the current draw from the lights total Watt value using ohms law I set up the red circuit for the lights. My lights are 15W each so, 30W / 12v = 2.5A. You need to add about 30% to allow initial spike in current at switch on so I chose to round up to a 3A limit. The unit can handle current spikes for the first second so this was adequate and works really well. I cut the relay and the handle bar switch out of the SW Motech wiring loom altogether, and extended the loom a little back to the ezCAN unit under the pillion seat by soldering additional wire on and sealing up with heat shrink sleeving. I retained the SW Motech waterproof connectors for the lights yet no longer need the handlebar switch to turn the lights on or off (as explained later) so no need to run cables around the handlebar anymore. The whole wiring exercise is much neater now with better weather protection.
I’m really impressed with the ezCAN unit, and CANBus itself. The lights can be programmed via the software to dim down at night and have two separate brightness levels, one for daylight running and nighttime. They are no longer simply on full for each. To switch current on or off the unit is programmed to use different existing switches on the bike e.g. for the red circuit I used for the lights the indicator switch cancel operation is reused so when pressed and held for 3 seconds toggles the lights on or off. Obviously there is no visual clue when riding (the indicator switch doesn’t light up) but the unit remembers the last state when the ignition is switched off so most of the time I ride with running lights on anyway. One simple option for the future would be to add a 10k resistor with small LED into the wiring loom as a visual clue near the front beak so I could look in and see if the circuit is live. It’s also possible to program the circuit to pulse when the horn is pushed causing the lights to flash as the horn sounds. Another programming option is to turn off the running lights when indicating in order to make the indicator light more visible to other road users.
A great product that works really well and made in the UK. I’m now looking to connect up other accessories e.g. wire my GoPro power, Phone and maybe buy a Denali Sound Bomb horn too
More info’ .. See: https://www.hexezcan.com/installation/r-series-lc/
