Pos and Neg are revesible.

Karl Wolz

|-----Original Message-----|The 3 wires are:
|
|positive, negative for O2 heater and "signal" (voltage output) to ECU.
|
|I gather the O2 heater element provides a sort of
|"convenience"; it heats up the O2 sensor so the engine
|management can get into closed loop more quickly. On a single
|wire sensor, this would be done with exhaust heat.
|