2021 Updates:

1: Symtec heated grips also go by the name Heat Demon. Amazon sells them for about $46. (Link.)

2: I bought a 1995 K75 with factory heated grips and one side didn't work so I decided to install some aftermarket grips. Instead of buying the Symtec grips I went cheap and bought a pair of these grips for only $10 on Amazon. (Link.)

They're 15W vs. the 18W of the Symtecs or OEM grips but they work pretty well. Instead of the big heat shrink tubing that came with them I just used electrical tape to install them:

I had to lengthen some of the wires but that wasn 't a big deal. I made a variable control for them like the one at the bottom of this page. Well worth $15 total.

 

Pre-2021:

Since I've had good luck with them in the past and they're readily available, I usually use Symtec heated grips.  They come with either a toggle switch or a round rocker switch.  The motorcycle version is good because it has different heating elements for each side since the plastic throttle tube and the bare metal of the clutch side conduct heat differently.

The best price I've found is here: PowersportSuperstore.com

Finding the OEM heated grip power supply:

 

And here's a PDF of how to install the Symtec heated grips with a BMW heated grip switch.  Most of it is applicable to other brands as well.

Install.Symtec.Heated.Grips.pdf

Another Option

The high heating elements on the Symtecs are pretty good but sometimes, in colder weather, don't put out enough heat.  The solution to this is to hook up both heating elements to a variable power supply. (You probably don't want to run both the high and low elements at 12V as that would probably be way too hot and might melt/warp the plastic throttle tube.)

An off-the-shelf solution is to buy a Heat-Troller or similar and hook that up to both elements on both sides.

A DIY solution is to buy a $3 PWM (pulse width modulator) on Fleabay and use a knob in a BMW switch blank to have variable heated grips hooked up to both elements of the Symtecs.

 Details on how to do this can be found at this link.

© 2013 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.