O2 sensor heating circuit

Anyone know how to/ the procedure to test the oxygen sensor heating circuit?
I installed a new set of O2 sensors and now have a malfunction in the upstream circuit. I replaced the upstream sensor at the suggestion of a mechanic, because it read too high of voltage. I then cleared the code/MIL light with a code reader and the code came back.
I am now getting a sensor malfunction and a heater malfunction code. My FSM says to refer to the DRB scan tool for test procedures, but I do not have that.
Any help would be appreciated.

P.S.- I switched back to the original sensor and still have a malfunction indicator. So I do not know if it is a coincidence that the heater circuit is bad or if the first new sensor caused an additional problem. I just changed the sensors as a preventative issue and had no MIL codes prior to the change.

I think the two wires that are the same color are the heater circuit. You should have continuity between those two but none from them to the other 2 wires. Did you bend a pin putting something together? I did both of them on my 96 tonight and they are small pins.

JoBo

My problem came from doing preventative maintenance.
I did not check the vehicle connector, but both the old and 2 new sensors give the same malfunction.
I went to another shop today and asked them their opinion.
My understanding of the sensor is that it puts out a signal to the PCM. They told me that other factors including a vacuum leak would cause this error.
Any thoughts?

Once you locate the wires (I don't have the manual at hand right now, but I think they were 2 white) for the sensor's heating circuit, check the resistance for 7 Ohms when disconnected. You shold have 12V and ground getting there with your key in RUN. There's a fuse and a relay in the Power Distribution Center (black box behind the battery, map is on the inside of the cover) for the sensor and a BIG connector in the engine compartment near the passenger firewall where the wires run through.
Hope this helps.

First off, thank you for the suggestions and replies.
Second, I found a pin backed out of the vehicle side connector. I reinstalled it and will test drive the Jeep today to see if that is all it was.
Again thank you!!