Heated Grip Failure

[PhilDinAZ]

On my 04 Roadster the throttle heated grip doesn't seem to be working but the left side is fine. Where are the weaknesses that cause the failures? What areas can I look at that might be repairable instead of replacing? If not repairable is there a good place to get a replacement for just the one side?

Didn't need the darn things in AZ but now that I'm in OH they will be essential.

[Beemeridian]

11

[iowabeakster]

In addition to what was said above, another place of common breakage is very near the grip itself.

The wire that runs to the grip heater actually runs through the inside of the handlebar. It enters in a small hole and exits beneath the control assembly. To see where it exits (underneath the grip) you pull the whole control assembly off the handlebar. This wire (not enough slack to accomdate full throttle opening and closing) has broke on a number of folks before. Splice with a little extra length and you're back in business for no money.

Do you have the BMW repair manual? On page 32.6 a diagram shows the handle bar assemply exploded. There is a number 7 on that diagram. The wire underneath the number 7 is what you're looking for. I am too stupid to be able to show that diagram in my post. Somebody else more computer savvy might be able to help with the picture.

[sweatmark]

The throttle-side grip failure is common. Experienced the same problem on our Roadster during warranty period, and will likely occur again now that warranty has expired, which might prompt a different solution.

The problem in our case was broken wire inside the handlebar on throttle side due to either insufficient slack or repeated bending and fracture. When you pull off the bar-end weight and look inside the confines of the handlebar, you will likely see a broken wire.

[iowabeakster]

I'm so proud of myself.... I did it! (learned how to cut a pdf file, change to jpeg, and now can post)

The wire we are talking about is right next to the number 7.

[CycleRob]

The problem I found early on when I was "taking things apart" in it's 2nd week was that I found the wire doesn't have enough slack in the portion inside the handlebar & twistgrip. Unbelievable. On a new bike too. You can follow the wire to the point where it comes out of the handlebar at the top of the bend in the pic above. First remove the bar end weight so you can see what's going on inside there. Then just push a 1" (25mm) length of the exterior wire into the handlebar, providing more slack. Lastly, put 2 tight zipties on the external portion so it cannot pull the internal portion tight again.

You may have to resolder or replace the broken power wire. I'm surprised it didn't blow the fuse!! A complete fix might also require removal of the twistgrip to find/fix/replace an internally broken portion of the wire. It moves a LOT in it's lifetime, so a breakage is almost a given at some point. Especially if you're a throttle jockey. Since the wire looses it's internal slack so easily by any tugs on the external portion where it comes out of the handlebar, it needs to be tightly restrained there.

There is also a factory mistake in a too tightly restrained wire harness. You have to cut a few zipties:



You may very likely have a broken wire right where those zipties restrain the wire harness. After you cut those zipties, it allows the wire harness to swing freely, without stress or any further bending damage. Those 2 zipties are totally unnecessary and they just cause big trouble.