Don't forget wiring to the O2 sensors. Wiring diagram here:https://www.subaruforester.org/threads/2004-p0032-replaced-o2-sensor-with-new-oem-solved.813119/
Interesting YouTube video: Disconnect positive lead from battery and connect wire end of 12v test light to + on battery. Connect other end of test light to wire circuit in question. If light goes on you have a short to ground.
