the abs loom is definitely sepearte to the car loom, although it plugs into it for control for the power from the ignition switch.

i don't know where the ecu should be on a 3 door, but on a sapph (both 2wd and 4x4) it is on the passenger side. but you definitely have a 3 door abs loom witht the yellow plug as sapphs had red or green