Oxygen sensors

[Matthewhatt24]

I have a 94 ranger xlt with a 4.0 previous owner removed the o2 sensors and plugged them and removed the wiring for them I need to get them back in because the truck is running rich but I obviously have to run new wiring so if anyone has a wiring diagram or has done this before etc help would be awesome

 

[RonD]

Welcome to TRS

I can't see a reason for previous owner to cut the O2 connector off the truck side, so have a good look for them, they should be behind the intake down low by the firewall, they are round 4 pins each

O2 sensors come with 4 wire lead attached and the round connector to plug into the trucks connector

O2 sensor #1 is the passenger side
O2 sensor #2 is drivers side

There is only ONE wire color difference

O2s are heated, so they have a 12v and ground as 2 of the 4 wires, light blue is 12v, black is ground on both

Then both sensors share a reference ground, orange wire
Then each has its own signal wire to the computer(PCM)
Passenger side, grey <<<<<<<<
Drivers side, red <<<<<<<<
If you find the connectors these 2 wires are the only way to tell which side is which

O2s are on the 2nd diagram but need 1st for where they hook up on computer