Will ride for picts
Join Date: Feb 2004
Location: Minden, NV, USA
Another, cheaper idea ...
I thought resistors were "solid state."
Hanshi, although I'm a mechanical guy, here's what I *think* would work: Just add a 2.5 Ohm resistor in series on the low setting wire. Based on Tim's numbers, the high setting on the BMW heating element provides 26 Watts of heating to the ol' backside. Assuming that the Russel seat heating elements have the same resistance (and that's a big if), then a 2.5 Ohm resistor in series with the Russel heating element will provide about 75% of the full heating power on the low setting. When you switch to high, the current will bypass the resistor on the low side and provide full voltage to the seat heating elements.
Based on the LED flashing on my heat troller, I think it works as a timing device, not as a variable resistor. I'm guessing that it applies full voltage to the heating element, but interupts the power based on the knob setting. So at full on, the power is never interrupted, and at a lower setting, the power is interrupted more and more. This is a guess, I haven't pulled out the ol' muli-meter to see what it actually does.
Disclaimer: None of the above has been validated for your specific conditions, but based on the casual numbers and information provided. If you attempt do this, and ruin the seat, or burn up the wiring or motorcycle and burn down the garage, its NOT MY FAULT. Consult a licensed professional or your BMW dealer if you are not comfortable.
V=IR, don't touch the live wire.
PS, how do you had "hard spaces" to this text editor? I tried to show an electrical schematic using keyboard characters, but the text editor throws out extra spaces.