I would not recommend connecting the wires together from the O2 sensor. Most sensors have three wires, one is the signal to the ECU and two are for the heater coil, used to help keep the sensor hot. If you send the 12v from the heater to the ECU it could be bad news.
The signal from a properly functioning O2 sensor to the ECU with warm engine should be a pulsing voltage approximatley 0.5v. The sensor generates this voltage on it's own, even without any wires connected.
Normally, just disconnecting the O2 sensor will put you in "open loop" operation and the car should run without electronic correction. Your fuel efficiency might suffer and the check engine light might come on but the car should still run.