Heatd O2 4 wire

Wires on 4 wire O2:

WHITE: Signal Wire
GREEN: Signal Ground
2 BLACK: Both black wires are the heater circuit wires.

Using a P28 ECU (and should work for most obd1 ecu's with 4-wire controls)

Run O2 Sensor signal (white) To D14
Run O2 Sensor signal Ground (green) to D22 (or any good Ground)
Run O2 Sensor Heater Circuit Control (black) to A6
Run the other black heater circuit power wire to (A25) or any good switched +12VDC source.