The BMW heated grips for the GS and their wiring can be frustrating when working on the machine or fault finding.
The information below is intended to assist & simplify the process of fault finding on the heated grips
There is an enhanced version in modifications which adds an external grip interconnection point
The heated grip rubber replacement pdf is from a forum thread with added information from a few other people.
F Series heated grip elements are wire wound elements which enable replacement of broken wiring and
hand grips. G Series are a molded grip with an acetate copper track element which is not easy to repair.
The element specifications are the same for all models.
Grip Element Resistance - 9.1 ohms
Half Heat Load Resistor - 2.5 ohms
Power Consumption @13.8v - 42 watts
Half Power Current @13.8v - 2 amps
Full Power Current @13.8v - 3 amps
Green/Black - Power from accessory socket to the switch
Black wire - Full power from switch to 4 pin grip socket
Orange wire - 1/2 power, switch to grips via load resistor
Brown wire - Earth from grips to socket in electrical box
The 1/2 heat load resistor is 300mm of resistance wire
There are two types of wire used in heated grips, Nichrome and Cuprothal. Nichrome cannot be soldered where Cuprothal can be soldered but is difficult at times. The BMW heated grip wire appears to be Nichrome.
It was difficult to obtain replacement wire of the right diameter and resistance. It is now produced in India and there is at least one source selling it in low quantity in Germany. It does not appear the seller exports from Germany.
Variable temperature controllers can be wired in to replace the 1/2 heat resistance wire. Basic information on the types of controllers available is in the pdf. The simple digital units are the best to use. Heated Grip Controllers
On the F650GS and G650GS 08-09 models the insulation on the wiring at the end of the hand grips shrinks back and can short on the handlebars and should be checked periodically. It can be pushed back into place.
The 1/2 heat setting of the BMW grips is achieved with a 300 mm length of orange resistive wire in the electrical box. Where a grip shorts out and the grips are on in the 1/2 heat position this wire will heat up and melt insulation and other wires in the electrical box. The fault is known to occur on many BMW models.
The wiring at the switches in the middle of the dash also breaks off and should be checked periodically.
The test procedure for 00-04 and 05-15 models is different due to the different locations of the on/off switch and testing the individual elements is a pain due to the need to remove the cowlings to access the electrical box behind the steering head. (The modifications section has a wiring change to make testing/replacement easy)
1/ Remove the switch mount in the middle of the handlebars (00-04) or the RHS switch cluster (05-15) and turn it over to access the wires at the rear of the switch.
2/ Use a multimeter to check the resistance of the grips to earth (black wire) it should be about 5 ohms.
3/ Use a multimeter to check the resistance of the grips to earth (orange wire) it should be about 8 ohms.
4/ With the ignition on use a multimeter to check for +12v on the Green wire. (Power to the switch)
5/ Turn grips on to full heat and confirm there is +12v on the Black wire. (Power to the grips)
6/ Turn grips on to half heat and confirm there is +12v on the Orange wire. (Power to the grips)
If the grips dont pass the tests then it is time to look in the electrical box to investigate further.