I have a 1991 f-250 with a 460. On my wiring digram the oxygen sensor has a wire that says it goes to the DIR flasher. Anybody know what that is? where it goes? Im getting ready to transplant the motor into my 1975 f-250 and am trying to make sure i know where all the wiring goes to before i start. Thanks in advance.

After some searching i know what the dir flasher is. Could someone please explain to me why the oxygen sensor is tied into it?

 

Ok, I'll bite! dir flasher?

 

yep thats what the wiring diagram says. all my research shows this to be the directional or turn signal flasher. Why would an engineer hook an o2 sensor to the turn signal flasher? Somebody straighten me out!!!!

 

Not seeing it!



So if your right turn signal starts blinking, your running either Rich or lean?(Joke)

I'll go as far as a shared ground location, but that's it!

 

my wiring diagram is showing o2 sensor as having 4 wires let me see if i can post a pic of it .

 

That would make it a heated o2 sensor. Still going w/ a shared Ground connection. Notice the multiple grounds off the Battery NEG in the diagram I posted.

 

i cant figure out how to get from paper to computer file.

purple/orange- Dir flasher
grey/lt blue-pin 29 computer HEGO
black- ground
orange-pin 49 computer HEGO ground as well as self test output, idle air bypass valve, map, maual lever position sensor, transmission, coolant temp sensor, air charge temp sensor, egr

i got the shared grounds, the o2 ground, the o2 signal input, still confused on dir flasher

 

Here's the schematic of the oxygen sensor for a 88. It appears the wiring is
similar to your 91. The 88 has no self test wire.

Bottom left corner shows the heated oxygen sensor.

On the 88 it uses a 3 wire sensor.
The output of the oxygen sensor goes to pin 29 of the computer.
In the schematic it's a Dark Green/Purple wire.

The ground for the oxygen sensor is the body of the sensor which screws
into the exhaust pipe bung. The ground for the heater circuit is a Black wire.

In your case the sensor has 2 ground wires. You can tie them together and
ground them.

The 12 volts for the heater element comes from the ignition switch.

When the ignition switch is in Run/On 12 volts passses thru the ignition switch and provides
12 volts to two circuits.

12 volts goes to Fuse #5 which is the Turn signal flasher.
12 volts also goes to a 20 gauge fusible link and then to the heating
element of the oxygen sensor via a Gray/Yellow wire.

 

awesome so i just need to supply an ignition fused 12 volt source. Thanks a bunch. T

 

Yes a fused switched 12 volts is all you need. It appears in later years, Ford started to monitor the heating element circuit and would set a trouble code if there was a problem.