I don't have any installation pictures available, but I expect that this wiring diagram of the fog light switch used in 2003 and probably other years of that era would be helpful to anybody planning on using one in a mod.
- The Bar Light is the light that signifies on/off.
- 'Illumination' in Subaru diagrams means a light that helps you find a switch in the dark. These are
always connected on both sides (No ground! No hot!) to special control circuitry that handles dimming and is not to be otherwise messed with lest it get blown out. The wires are generally colored Orange with a White Stripe, and Violet. You can tap off of them at nearby switches or at unused connectors intended for options that you don't have. But only use this circuit for its intended purpose and with bulbs of similarly low current requirements, or you risk an expensive blowout.
- Circuits 1 and 2 are for independent applications that are to be simultaneously controlled by the switch. Not all implementations would use both circuits. But if you do need to control two separate things at the same time, don't try doubling them up on one circuit, as very strange things can happen.
- +12 is whatever sort of power you need to use for your application: key on, always on via existing circuitry, straight from the battery—whatever is right in your situation. There is no specification regarding the switch's maximum current rating, so high power applications such as lighting would normally use the switch simply to control a relay, with the relay switching the heavy current straight from the battery via a fuse.
Note that Subaru uses non-standard terminals on its switches, which are difficult to connect to. The best approach is to get the mating connector and its wires from a Forester at a junkyard, and splice it in. (ToddLamp was a big collector of these. Now that he's sold his Forester, he might have some available for sale.)
If you intend to mount the switch in an unused section of a switch panel, you just might find an appropriate connector dangling by itself behind the panel, part of a standard harness intended for an option you don't have. Consider it fodder for cannibalization. And with luck and careful analysis, you might find that some of its wiring is already OK for your new application. Illumination would be a strong candidate.