Join Date: Aug 2005
Location: Aurora, CO, USA
There has been a lot of discussion about the new Canbus and its implications on the usage of aftermarket equipment.
The Canbus system in its fullest implementation could allow for a single communication line and a single power supply to be shared among all components. For example a turn signal could be a module, supplied with power and the data communication would tell it to turn on and off. Additionally all of these modules would not need to be fused as they would monitor current and if a short or other fault occurs, would disable the circuit until the fault was cleared. There could be a module for the headlights, horn, brake lights, etc.
The implementation on our motorcycles is the same except that all control “modules” are contained in a single chassis control module called the ZFE. This ZFE has inputs from all switches and controls and outputs to all components. Each brake light switch has its own input as does each switch on the handlebar controls. Sidestand switch, clutch switch, neutral, etc are also input to the ZFE as individual inputs. Each powered component such as horn, lights, windshield, etc. has its own output from the ZFE. The ZFE has the software logic to determine what output occurs based upon one or several inputs. Each output is fault protected and most are fault tolerant as well, meaning that as soon as a fault is corrected an output will resume its normal function without the need for external intervention.
We do not need to be afraid of attaching external devices to the Canbus equipped bike, we just need to be careful not to overload any of the ZFEs protected outputs. Any of the outputs can also drive a relay without fear of triggering a ZFE fault. Some of the ZFE outputs such as the one for the taillight, monitor for over as well as undercurrent situations. An undercurrent situation (burned out bulb) in the taillight will cause the ZFE to run the brake light at reduced brightness for safety until the defective bulb is replaced. Under that situation you will see a fault indicated on the instrument panel. As soon as the bulb is replaced the fault will clear and normal function will resume. Any additional lighting for brake lights or taillights should be implemented using relays and most importantly the original bulbs must be left in place or a fault could be triggered. LED taillight replacements must be designed to account for the ZFE monitoring, by employing circuitry that draws enough current to let the ZFE “know” that the bulbs are functioning.
For external equipment I would recommend one of two different approaches. For small equipment such as a GPS, radar detector, communication system or satellite radio, there is an auxiliary equipment connector just in front of the battery. It is a three-pin connector consisting of a ground (brown wire), power supply (red with white trace) and speed pulse (blue with green trace). A mating connector with pigtails can be purchased from your dealer using part number 83 30 0 413 585 for around $25. I have successfully used this connection on my K1200s, Michelle’s K1200S and my K1200GT. It drives an Autocom Super Pro AVi intercom system, a Garmin 2720 GPS and a Pioneer INNO XM radio on all three bikes. Since this is a fault protected output no fuses are needed. The Autocom draws less than 150 milliamps, the GPS well under 1 amp and the INNO can draw as much as 1.5 amps when charging its battery. The auxiliary output drives all three items without a problem. An additional feature is that this auxiliary output is a “retained power” output, meaning that it remains active foe a few minutes after the key is turned off. For this reason I would not recommend this output to control a relay for auxiliary lighting.
For auxiliary lighting I would recommend a relay driven from the low beam headlight wiring. Using the running light circuit to drive this relay takes it out of the “load shed” group and will allow your auxiliary lighting to remain on while starting the engine. Using the low beam headlight wiring (yellow with white trace) has the advantage of remaining off until the engine is started to prevent unnecessary load on the battery during the high load event when starting the engine. An additional feature is that this allows you to turn your key on to enable the GPS, radio or other accessory without the headlight or auxiliary lighting being on and draining the battery. On the K1200S the wiring to the headlight is easily accessible in behind the cover just to the right of the instruments. On the GT the wiring is in the same place, but lacks the exposed wiring that is on the S. I had to cut through a layer of cloth tape in a harness to expose the yellow/white wire to control the relay for my MotoLights. The actual plug and wiring for the headlights is behind the instrument cluster. There is no reason to fear using this headlight wiring to control a relay, by nature the headlight control line must be robust enough to control between 5 and 10 amps of lighting allowing for one or two 55-watt bulbs.
There is a software update to the ZFE when the bike is fitted with a Xenon headlight (not available in the US) so there may be some concern that the ZFE is looking at a minimum current to the headlight circuit to monitor for a burned out headlight bulb. I am not sure how an aftermarket HID add-on will affect the ZFE monitoring.
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