I got a 94 loyale that the illumination is not working after I installed a new stereo. I tried constant and switch power and either it stays on regardless what position the headlights/key are in or on the switch it comes on and off but the headlight switch won’t turn it off when the headlights are turned off. How do you hook it up to work with the headlight switch?

What you’ve done is crossed an earth switched wire with a positive switched wire. This will do your head in. 

The specific wire could be any of your power sources or the illumination wire if your head unit came with one. This is the wire I would suspect to be the issue. 

Work out which wire and we’ll go from there as I’m not 100% what the fix is. 

Cheers 

Bennie

Test light success.

It turns out that the 1993 model quietly had it's wiring changed around. Many sources online I have found claim for the constant 12V to be on the red/green pins and the illumination on solid red (which consequently, also attach to two pin connector with the same colored wires).

This is WRONG.

 Test lighting the supposed red/green and red wires at the connector will show there is no power through these wires, despite them being connected to both the stock head unit's harness and the two pin connector coming off it and back to the car, regardless of key state (off, accessory, on).

 The blue yellow wire (pin one) will only power in accessory and on positions. Thus, 12V switched (or ignition as it can be labeled on aftermarket diagrams) has been located.

 Last, but certainly not least, is the mystery one pin connector with a white clip. It is ORANGE from the stock unit, and at the car side, changes to GREEN. Putting a test light to it in off will show power, as well as all other key states EXCEPT start (engine crank, this is normal).

This is the constant 12V (or battery connection) that is SUPPOSED to be the red/green wire (or perhaps, only applies to years prior; I can only speculate why Subaru did this and won't begin to).

 So, let's recap.

 Constant 12V - Orange from stock unit, green after single pin connector (aftermarket manuals may call this 'battery')

Switched 12V - Blue on stock unit, blue/yellow after eleven pin connector (aftermarket manuals may call this 'ignition')

Ground - Black on both sides of eleven pin connector

Wires in question:

http://i1078.photobucket.com/albums/w482/tincan93/Mobile%20Uploads/20141116_070451.jpg - Constant 12V

http://i1078.photobucket.com/albums/w482/tincan93/Mobile%20Uploads/20141116_070352.jpg - Switched 12V

http://i1078.photobucket.com/albums/w482/tincan93/Mobile%20Uploads/20141116_070410.jpg - Ground

Of course, the result will become clear when you jam it all in the dashboard and turn the key on:

There is no illumination, nor remote power on lead for the amplifier (unless you installed one), and the power antenna wire is also unused (again, unless you installed one).

 

Again, I used a test light and checked everything in each state of ignition. I know this gets searched up a lot online, but I'm not responsible for what you do to your vehicle, nor can I confirm if this will work in your scenario. That being said, use caution and common sense.

 

Hopefully you can make use of this information if you decide to install an aftermarket stereo.

This is the problem I’m having.

. 

All sorted then! You’ve got the car’s illumination stuff sorted and the stez works as it should now? 

Lucky you didn’t damage the headunit! 

Cheers 

Bennie

So that previous post from another member from a post years ago. My stereo works fine I just don’t know where to hook up my illumination. It’s been pretty frustration. 

You might need to set up a relay - triggered using the wiring for the ash tray light or illumination light for the heater controls/cig lighter. 

Then run a separate power wire controlled by the relay to the headunit’s illumination wire. This should get around any negative earthing issues etc and have the function work as you’re wanting. 

Cheers 

Bennie