2, one before and one after the catalytic converter
Yes
Exhaust system.
You can not bypass it. The oxygen sensors are required for a proper running engine.
no
Its located in the exhaust pipe on rear of engine.
No.
21 is for the oxygen sensor reading staying at center.
No.
2, Before & after the catalytic converter.
Next to the oil filter and oil pump. Wheres two sensors down there its the one on the left.
There isn't a vacuum line going to the regulator on a 1998 Dodge Caravan.
No. A 1998 Dodge does not have a reset button or kill switch.