96 jetta 2l code p0135

Just replace the Cat converter on my Jetta now getting code P0135 which I know is a heater fault code for the O2. I suspect may have broken a wire on the heater curcut to one of the O2 sensors during take down / install. Is there an easy way to tell which sensor may be broken or some other place to look. I tried disconnecting the forward O2 and the Rear O2 wiring harnesses one at a time and still ghet the same 135 code and then get 134 if either O2 is disconnected. I had hoped it would help me figure out which one was bad by giving different codes not the same one..

Any ideas appreciated.

Bank 1 is the front sensor before the catalytic converter. The two wires that are the same color are for the heating coil in the O2 sensor. Unplug the sensor and put a very sensitive voltmeter to the plug coming from the car. Do not put an ohm meter to the O2 sensor, it is very easy to burn out the heating element.