MSefi.com read only forum (Jan.15,2018)

how should I go about wiring the ford 4-wire heated o2?

i have traced my wires through schematics. the ones that are self explanatory are dedicated ground and eec power but the other two are quite vague.

one is shown to be going to the EGR system and the other goes back into the harness somewhere.

can someone shed some light on how this should be wired up. I know that this sensor needs some power for the heated part.

thanks

patrick

It would help a little if you explained which end of the harness you are looking at, the wire colors are different depending if you are looking into the connector at the sensor, or somewhere else, like the EEC connector.

Also it makes a difference if you have the TC sensor and harness or the Mustang sensor and harness.

It's easiest to corrolate the sensor wires to the harness wire colors, since the sensor wires are just black white or grey.

TC wire harness -

grey/yellow = heater power +12v
black/lt green = Ground
dark green/purple = signal to EEC pin 29


The stock TC sensor is a three wire sensor, so if you have a four wire sensor IIRC hook the black wires to 12v and ground, the grey or white wires are the sensor, one is ground, the other is signal.

4 wire sensor is wired like this -

ill have to go home and see what exactly each one was described as.

its the mustang 4-wire sensor from my 93 lx n/a.

ill get the details scott

thanks

alright this is what I have as far as schematics goes:

black- dedicated ground

gray/light blue- EEC to o2 sensor

orange- fuel sensor ground to EEC

gray/yellow- I traced this back to the ignition switch

so using the picture:



I should be looking at:

black-ground

gray/light blue- o2 wire in ms harness.

orange- signal return

gray/yellow- +12v since it is traced to ignition switch.

does this look correct?

thanks

patrick

1fastfox wrote:alright this is what I have as far as schematics goes:

black- dedicated ground

gray/light blue- EEC to o2 sensor

orange- fuel sensor ground to EEC

gray/yellow- I traced this back to the ignition switch

so using the picture:



I should be looking at:

black-ground

gray/light blue- o2 wire in ms harness.

orange- signal return

gray/yellow- +12v since it is traced to ignition switch.

does this look correct?

thanks

patrick

Looks good from here.