I am not sure how the signal wire is controlled by the ECU, so it could have voltage.

Shorting the electrical connector to temp switch A turned on the radiator (passenger side) fan. You need to first find out why the a/c(driver's side) fan did not turn on and fix this first.

Jump that connector again and hit the a/c fan motor housing with the handle of a screwdriver with light/medium force. Does the fan turn on? Turn off engine.

Unplug the a/c fan and test for 12V at the a/c fan connector with the temperature switch a connector jumped and the engine running.

After you figure out the a/c fan, then we can see why they fans do not turn on when the a/c is running (different electrical system to turn them on).

 

The blue wire for the ground signal shouldn't have voltage. The wire circuit for the blue wire is connected with the radiator fan control module, temp switch A, ECM to both A/C condenser fan relay and radiator fan relay. Either one of those can provide the ground source to energize both respective relays to close the relay contacts. On one side of the relay, power is already provided with the ignition on, it just needs the ground to energize the relay to close it.

 

That diagram you made is correct. Blue/yellow is bottom right and has close to 0ohms. (.06 w/ multimeter@ 20k)

 

The A/C condenser fan problem is starting to sound like an issue with the blue wire. This blue wire is to provide ground for the condenser fan relay.

Since the A/C condenser fan motor has it's own ground wire (a separate black wire from ground G281) and there is power at the relay connector White wire; if you were to use a jumper wire on the disconnected relay harness connector from the White wire to the Blue/Yel Wire, the condenser fan should run even without the ignition on.

Just to rule out the relay, did you try swapping this particular relay, even though you mentioned you swapped relays previously?

 

On second thought, if the blue wire is carrying voltage when it shouldn't, you may not want to swap a good relay into there; to avoid the possibility of damaging the good relay. Maybe try the condenser relay elsewhere.

 

I only swapped the cooling fan relay in the fuse box, never swapped the condenser relay. The only other relay similar to the condensor relay is the ?compressor? relay next to it, which isnt engaging either (likely due to the same wire?)

Since the blue wire is only seeing voltage with IGN ON and is seeing the exact same voltage, its likey merged with the yellow wire somewhere correct? Where is it likely this is happening, the fan timer?

As soon as i take care of some Errands, im going to replace the temp switch and go back to troubleshooting this blue wire.

 

The blue wire may have a possible short somewhere at the same relay connector, or the wiring at 8P Gray Connector C309 (located left hand corner of engine compartment, behind A/C receiver), or 20 cavity Junction Connector C457 (located behind dash, above brake pedal).

I would more suspect the same relay harness connector wiring or at Connector C309.

Edit: Although it can be at the fan timer (aka radiator fan control module). I would think this is less likely, since it looks like if the A/C is turned on, the ground source from the ECM (if functioning properly) can also go through a separate path to the A/C condenser fan relay instead of just through the fan timer. -- Both fans did not run when the A/C was turned on.

 

Wasted time trying to handle the temp switch, only to find out the parts store gave me the wrong one. Drove to another and hopefully got it right this time. The switch should be a 22mm with a probe on the end, correct?
And after I change the switch out, what should I do to test the ac circuit and find my short?

 

For the switch, sounds about right, just make sure to check the temperature it suppose to close at; most switches will have the temp. number stamped on it for when the switch should close (for example, 93).

This image is a photo of an aftermarket switch for your car.



To check for the short, if it is due to the wiring, starting checking visually. Wiggle, separate wires, etc. if you can, along the harness and check that blue wire terminal with the voltmeter while you're doing this. If I can, I'll try to think up some other things to try to do to narrow it down if you don't quickly find it.

 

You can also take a look at the harness connector to the radiator fan control module (aka fan timer). Check the wiring and connector terminals there.