knnelg
Registered user
Hi Guys.
My 2008 R1200GS recntly developed a problem with her heated grips (great timing as we've had some rather chilly mornings over the last few weeks) it started as an intermittent problem, but then turned permanent.
I used the wiring diagram from http://www.r1200gs.info/R1200GS-WD2.pdf to try and work through the possible causes.
I striped the right hand switch assembly and confirmed the heater switch was working correctly. which left me the following other possibilities...
1) There is a fault in the ZFE Control module
2) There is a fault in the 'BMS K Control Module'
3) There is a break in one of the wires from the handlebar switch to the ZFE or the 'BMS K Control Module'
4) There is a fault with one of the several sensors used by the ZFE (or the BMS K Module) to determine whether the grips should be powered or not (I understand there is logic to prevent the grips being powered below a certain RPM or low battery voltage etc. etc.)
Before I started, there was no voltage at the heating elements regardless of the switch position and the engine running, revs etc.
The cold resistance of the left/right heating elements was measured at 7.2/7.4 ohms (which would draw around 2 Amps @ 14 Volts, producing around 30 Watts of heat per grip)
After removing the tank, I managed to locate the relevant connector (top one) on the ZFE controller. and checked all the wires from the switch and heating elements and confirmed there were no open circuits. all the connectors and harness were in excellent condition, no signs of corrosion, damage etc.
Unfortunately, as the tank was off, and also owing to the design of the ZFE connectors, it was impractical to try and run the engine and measure connections, so I gave up and put everything back together.
Once everything was back in place but just before I reconnected the heating elements, I took a further voltage reading on the heating element connectors and this time I measured 14+ Volts (Engine running) with the switch in position 2. When the switch was moved to position 1 (low power) the voltage remained at 14+ BUT was 'pulsing' at a frequency of around a second or so (difficult to say as I was just using a digital voltmeter) so it looks like the reduced heat mode is achieved by alternately switching the power on/off.
The final result is the grips are now working again.
As summer has returned (balmy 7 degrees today) we went for a ride up the northumberland coast today, and the grips worked fine every time I tried them.
I'm not particularly happy, because I found no problems in all the testing I done. My only explanations are that...
1) There is possibly a faulty connection on one of the wires and by removing/replacing the connectors and disturbing the harness etc, then I've temporarily made the connection again.
2) The removal of the connectors from the ZFE has removed power and possibly reset any error code in the unit.
3) There was some condition detected by either the ZFE or BMS-k module which inhibited the heaters and this condition has gone (for now), but in the abscence of any documentation I'll never know what these could be.
I've done searches and asked around, but so far I can't find any decent documentation on these ZFE & BMS control modules. Anybody know if the details are available outside the halowed premises of a BMW service centre?
The bike goes in for it's anual service in a few weeks (Coopers, Sunderland), I'll ask them to check error codes etc, but I don't hold out any hope of getting a proper explanation.
Regards,
Glenn
My 2008 R1200GS recntly developed a problem with her heated grips (great timing as we've had some rather chilly mornings over the last few weeks) it started as an intermittent problem, but then turned permanent.
I used the wiring diagram from http://www.r1200gs.info/R1200GS-WD2.pdf to try and work through the possible causes.
I striped the right hand switch assembly and confirmed the heater switch was working correctly. which left me the following other possibilities...
1) There is a fault in the ZFE Control module
2) There is a fault in the 'BMS K Control Module'
3) There is a break in one of the wires from the handlebar switch to the ZFE or the 'BMS K Control Module'
4) There is a fault with one of the several sensors used by the ZFE (or the BMS K Module) to determine whether the grips should be powered or not (I understand there is logic to prevent the grips being powered below a certain RPM or low battery voltage etc. etc.)
Before I started, there was no voltage at the heating elements regardless of the switch position and the engine running, revs etc.
The cold resistance of the left/right heating elements was measured at 7.2/7.4 ohms (which would draw around 2 Amps @ 14 Volts, producing around 30 Watts of heat per grip)
After removing the tank, I managed to locate the relevant connector (top one) on the ZFE controller. and checked all the wires from the switch and heating elements and confirmed there were no open circuits. all the connectors and harness were in excellent condition, no signs of corrosion, damage etc.
Unfortunately, as the tank was off, and also owing to the design of the ZFE connectors, it was impractical to try and run the engine and measure connections, so I gave up and put everything back together.
Once everything was back in place but just before I reconnected the heating elements, I took a further voltage reading on the heating element connectors and this time I measured 14+ Volts (Engine running) with the switch in position 2. When the switch was moved to position 1 (low power) the voltage remained at 14+ BUT was 'pulsing' at a frequency of around a second or so (difficult to say as I was just using a digital voltmeter) so it looks like the reduced heat mode is achieved by alternately switching the power on/off.
The final result is the grips are now working again.
As summer has returned (balmy 7 degrees today) we went for a ride up the northumberland coast today, and the grips worked fine every time I tried them.
I'm not particularly happy, because I found no problems in all the testing I done. My only explanations are that...
1) There is possibly a faulty connection on one of the wires and by removing/replacing the connectors and disturbing the harness etc, then I've temporarily made the connection again.
2) The removal of the connectors from the ZFE has removed power and possibly reset any error code in the unit.
3) There was some condition detected by either the ZFE or BMS-k module which inhibited the heaters and this condition has gone (for now), but in the abscence of any documentation I'll never know what these could be.
I've done searches and asked around, but so far I can't find any decent documentation on these ZFE & BMS control modules. Anybody know if the details are available outside the halowed premises of a BMW service centre?
The bike goes in for it's anual service in a few weeks (Coopers, Sunderland), I'll ask them to check error codes etc, but I don't hold out any hope of getting a proper explanation.
Regards,
Glenn
