Question edited for clarity.
Question moved to model category.
The connector must have been on it when you replaced it? If you just noticed nothing was connected, there can only be a couple of reasons you can't find it.
1. it is tucked away somewhere out of sight. The wire will only reach so far and it has to come out of the main wiring harness.
2. The connector got loose and it got torn off. In which case, you are looking for just wires.
https://www.google.com/search?q=2002+jeep+liberty+sport+replace+downstream+o2+sensor
Sounds like an electrical connection. But which one? First start at the battery. Does it have 12.5+ volts? Does it stay at 12.5 while trying to start? If not then have the battery tested. If yes check to see if 12.5 volts is at the fuse box.
Check to make sure the battery is properly grounded to both the engine and frame.
That would depend on the reason it stopped working. Many newer vehicles have theft protection systems for the radio that will disable them if power is interrupted to the device. In that case, there is usually a code that must be inserted into the radio via the selection keys to re-enable the device. This code was provided to the original buyer by the dealer. They tell the owner NOT to store it in the car, as thieves usually steal both the radio and the owners manual in order to get to the code when the owner writes it into the manual. Thus, often when the car is sold, or even if the owner misplaces the code, when the car is serviced or the battery gets replaced, it can be a problem getting the radio back to working order. A lost code requires involving the dealership. If the problem is not with a code, the radio just isn't working, then after checking the fuse to ensure that it has power available, if it is not working, then replacement is the viable option.
? 7:14https://www.youtube.com/watch?v=yZWOx-zL_7w
Nov 2, 2012 - Uploaded by PrecisionLED
How to install Interior LEDs on 2010+ Jeep Grand Cherokee. ...Grand Cherokee A/C Control Unit Light Bulb Replacement (WK)
