1995 YJ7 o2 sensor 2500

I read the check engine light codes w/ an autoxray codescout 2500, and got the following 2 codes:

21
oxygen sensor bank 1 position 1 shorted to high voltage


33
open/short detected in a/c clutch relay


So here are my questions:
1. "shorted to high voltage" - does that mean it needs to be replaced? If so, where is it on the vehicle, and if not, what should be done to fix it?
2. regarding the 33 - I don't have a/c, so I'm pretty sure I don't have a cluth relay for the a/c...unless it's an electrical thingy for future use. Should I worry about that, and if so, how can/should it be fixed?

 

The O2 sensors are located in the exhaust pipes; one will be close to the exhaust manifold in front of the catalytic converter (O2-1). The other sensor will be after the converter (O2-2). Both of theses O2 sensors have heating elements built into them, to warm the sensor quickly and get them online faster.
Most times when code 21 sets it turns out to be the heater element that has shorted to the signal return circuit. I would replace the sensor clear the code and try it.
As for the code 33 the computer is looking for a voltage drop across the AC clutch relay, when it doesn’t see one because this vehicle doesn’t have AC; the computer sets the code. It’s a software issue in the programming of the computer; don’t pay it any attention.