Your description is not clear enough to tell which O2 sensor you are referring to. Most likely your 1996 Dodge Dakota has 4 O2 sensors. Bank 1 sensor #1 & #2 and Bank 2 sensor #1 & #2. Bank 1 will be the bank where cylinder #1 is - The left bank (drivers side) on your 5.2L engine. Sensor #1 is the one closest to the engine and #2 is next in line, if there is a #3 sensor that would again be next in line. Having a sensor #3 is very uncommon. You can think of sensor #1 in front of the catalytic converter and sensor #2 behind the converter if that helps.