basic transistor question

[stevieg]

i need to control a 2 wire idle control motor with a negative pwm signal coming from an ecu going through a transistor what do i need PNP or NPN and how sould it be connected? i will most likely be controlling the negative side but can control the positive side if necessary .
if it helps its a haltech sprint 500 ecu using a vw golf mk3 throttle body

thanks Steve