[QUOTE=OAP Pete;6840392]no polarity does not matter....wonder if the Black ECU is faulty...that dropping back to 1v...OK...but should be zero when fully Hot....there seems to be High voltage there as soon as plugged in...going to have to wait till you have new sensor...i fear the Black ECU may be faulty..do check power as said.......in normal running the pressure actuator is dead...waiting for the water sensor to it tell it..ohms changed......next starter operation ohms alter....then increased pressure