RTV (silicone) posioned O2 sensor

[firsthere]

I cannot tell which, the only pair with a measurement from the Ohm setting.

 

[rockola1971]

I cannot tell which, the only pair with a measurement from the Ohm setting.

Heres a schematic for the 04 Tahoe. The symbol on the left of each sensor with the diagonal arrow pointing up and to the right are the actual 02 sensor of the whole sensor. The squiggly symbols to the right of each sensor element are the heaters. So just look at the wire colors and measure across the correct pair at each sensor. Each heating element circuit will have a pink wire on one side of the element. Just touch your meter the corresponding on the sensor, etc. (with wiring harness unplugged from sensor).

Fun Fact: The heater part of the sensor is fed power(12v+) by the 15a fuse directly to the sensor heater on one side. The PCM provides the ground on the side. ON the 02 sensor part of it the PCM provides power and ground for each side of the sensor part.