03 Outback Electrical issues

[Ceramiclover]

I have found a link to the JDM FSM.  Not sure if i need the USDM instead.

 

previous owner cut some corners.

He had overfused the illumination and used it to feed the taillight clearance circuit, which shows no voltage.
 

When i measure voltage on illumination fuse with lights off, I get 2.5v.

On headlight fuses, I get 1.5 with lights off.

 

there is a wire run through the firewall to the back of the fuse box, but i think i need to pull the wheel and fender liner to see where it goes...  

[Ceramiclover]

After a lot of time and struggling to follow subaru diagrams, I found that the park light switch was not providing continuity on its normally closed circuit.  I jumped it and all taillights work now.

Now its time to figure out what the previous owner did with the airbag circuits

[Fairtax4me]

That looks safe.

 

Check into reading the airbag codes. Its pretty simple, and the codes will tell you where to focus your efforts.

[Cougar]

There is a taillight relay in the dash fuse panel that passes power to the rear lights. The relay is turned on with the light switch, which makes a connection to ground to the relay coil. The PARK switch on top of the steering column passes power to the relay circuit in the OFF position. In the ON position the switch bypasses the taillight relay.

[Ceramiclover]

my code reader is failing to communicate with the srs ecu.  checked fuses.  need to check voltage at ecu next.  promise not to shoot power or ground into it or flip it over while plugged in.

 

The park switch wasn't doing anything, so i just jumpered the n.c. connections and the system works.  i also could not tell from the diagrams which was the taillight relay.

 

And since the circuit was missing 12v on its control side, i could not feel/hear a click.

 

not used to subaru wire guides.

Edited May 12, 2016 by Ceramiclover

[Cougar]

I think fuse 11 in the dash fuse panel provides power to pin 16 of the OBD2 connector. The TL relay is physically located in the dash fuse. It is real clear using the factory diagrams. Power to the TL relay coil comes from the ignition switch via a green wire which ties to other fuses also in the panel. The light switch grounds the other side of the relay coil to turn it on. If power isn't getting to fuses 6, 11, 17, and 18 then check the green wire back to the ignition switch.

[Ceramiclover]

Fuse 5 was not getting power because of the park light switch. that issue is fixed.

I can communicate with other ECU's, so i am not concernedd about dlc power.  airbag light is on and i only can't comm with airbag ecu.

Edited May 12, 2016 by Ceramiclover

[Caboobaroo]

Because the airbag computer is a flash code system.

[Ceramiclover]

thanks. i will look into that