Under dash plug
 

There is a 2 wire plug. brown and black striped red wire. Small plug at the end. Don't know what it plugs in to.

check the electrical troubleshooting manuals here: http://www.318ti.org/files/showentry.php?e=10&catid=1

if you have an older car, I'd recommend grabbing the 1997 one too, since that is OCRed and you can search it easily, then reference your year's manual for any differences.