1992 subaru legacy wagon tail lights busted out

run the fault but all you describe is operated from the VSS sensor ( vehicle speed sensor)
it tells the cruise control the vehicle speed , tells the TCM the vehicle speed so that ratios can be changed, activates the speedo,and will report with a check engine light to report a transmission problem
run the fault codes first

You do know that on Subaru's there is a switch on the steering collum that runs the running lights? If that's off the mark, then check your fuses. The one you will be looking for is marked "tail" in the fuse box.

Did you change the radio recently..if so you tapped into the wrong wire...and if not then I would say you have a bad headlight switch or a broke ground dome where

There are 4 screws that hold that light in the pocket. Keep looking under the carpet.

Dude! This is a common issue..there is a switch on top of the steering column for the 'parking lights'. It needs to be turned off....I'll bet that's it.
Good luck,
TD

In side the trunk behind the light you need to fix is a small access panel. Just open and replace bulb. Very simple and straight forward. Good luck and have a great day.

You begin by opening the rear-lid.
Remove the plastic panel.
Turn backward the bulb-holder.
[This will make it come off its housing]
Push-in the bulb, and turn it backward.
[it comes off]
Reverse these steps for installation.

you ave to change the socket that bulb goes in

1. Relieve the fuel system pressure.
2. Disconnect the negative battery cable.
3. Remove the rear exhaust pipe and muffler assembly.
4. On All Wheel Drive (AWD) vehicles, remove the rear differential assembly and the rear crossmember. You do not have AWD so this step is not for you
   
5. Remove the fuel filler cap and drain the fuel into a suitable container.
6. Remove the fuel filler pipe protector.
7. Raise and support the vehicle safely on jackstands.
8. Remove the fuel filler, air vent and delivery hoses.
9. On AWD vehicles, disconnect the air breather hoses and evaporation hose from the pipes.
10. Support the fuel tank with a floor jack or equivalent lifting device.
11. Loosen the attaching bolts and lower the fuel tank slightly.
12. Disconnect the fuel pump harness
    

The one thing youll find with subaru's is that they like to put nuts in funny places that are hard to access. There are either 3 or 4 nuts holding the tail-light assembly in place, which means youll need to take out most of the inner panels to access the others. You should not need a sealant unless the rubber seal is done for or there is water inside the car. Hope this helps