Originally Posted by
tunaglove
Well Im just about out of ideas for you.
Seems strange to get a heater error due to an air leak but I guess I would turn towards looking for that.
10.45 volts seems a little low but you have covered the basics. Since you are already under there compare the pin 1 of the other secondary O2 sensor to see if it is 10.45 also. I know you are laying in the mud and cold and you qualify for the tough guy award, I know that is NO FUN! You could try ohming out the other heater wire that goes back to the ECU to make sure that is connected. That is in the schematic I noted earlier.
That's about all I can think of for now sorry.
I'd like to suggest measuring the heater voltage under load. Keep the sensor plugged in and measure the voltage across the two heater pins. If you have a high resistance in the wiring, having a load on the circuit will drop more voltage across the bad point and your meter reading (measured voltage) will be lower. If this is true, the next step that I'd do is measure pin 1 to a good ground. If the voltage is close to battery voltage then you know that the other wire or connections are suspect.
For reference, do this procedure to a known good sensor and you will know what you are looking for.
What is the measured voltage at the fuse, and across the battery? I haven't looked at the wiring diagram yet, but this will give a good start on diagnosing the wiring.