94mb7311

Hi, I have a 94 C220 (150,000 miles). I disconnected my rear O2 sensor from the wire coming from the ECU and found that is not receiving any power (12 V) from the car once the car is turned on, I checked all the pins with a multimeter to verify. I am wondering if anyone knows if there is a fuse or relay associated with the O2 sensor heater circuit, which may be causing no power to be present at the connector. If not, where is the other end of the connector (in the hood) so I can check it there to rule out a break in the cable? After disconnecting the sensor, the cable runs from under the car into the car, so I cannot trace it back. My actual O2 sensor is ohming overload on all pins, so I think it is bad also. Any help on this would be great. Thanks.