I appreciate the advice thus far, but let me make it a bit more clear.

1) PWM isn't an option. I'm making a little "dongle" board that inserts where the OLD motor went. Therefore I only have access to the 12v and ground.

2) I don't have access to any further pins on the controller

3) The operation is onoff only.

This voltage must be split in half.

Reguardless of torque, decreasing other important motor factors, etc. It's a totally different motor (runs at 6v fine) that I have to use.

There must be some passive way to do this! Like 5 or 6 diodes in it's path, or one huge resistor in series.

Right?

Thanks thus far!
J