Need to replace a headlight assembly for a 2006 Subaru Outback.

Both high and low beams quit or just low beams?

There should be separate fuses for high and low beams on a Prius. If one of your headlight bulbs is bad, it could have blown the low-beam fuse. Check for blown fuses behind driver's side headlight fuse panel. If new one blows, replace headlight bulbs and try again.

On 2004-2009 Prius, driver's side headlamp bulb can be replaced by removing hold down screws and folding fuse panel upward to access rear of headlight assembly. Large round cover with 3 tabs unscrews about 1/4 turn to remove. It's really tight and held by friction of large O-ring so it'll take some muscle but it will eventually give. Be careful replacing bulbs as metal clips can be easily installed incorrectly resulting in tilted headlight beam. 3-tabs must rest on flat surfaces on mounting area before spring clip can be latched in place. 3-prong plug can be wiggles sideways/up and down to remove from bulb.

Whether they become damaged in an accident or simply burn out over time, your Subaru Outback's headlights may eventually need to be replaced. Fortunately, once you've purchased the right replacement bulb for your model year, performing the repair yourself is relatively easy. These instructions only apply to Outback models made after 2000.

1. Undo the clips on the air intake ducts using a screwdriver and remove the duct from the engine compartment (driver's side bulb removal only.)
   

2. 2

   Loosen the secured clip on the washer tank with a screwdriver and slide the tank horizontally to allow easier access to the headlight assembly (passenger's side bulb removal only.)
   

3. 3

   Turn the bulb cover counterclockwise and remove it from the assembly.
   

4. 4

   Disconnect the headlight electrical connector and undo the assembly retaining spring.
   

5. 5

   Pull the old bulb directly out of the socket and replace it with the new one. Press the retaining spring back into place and reattach the electrical connector.
   

6. 6

   Replace the bulb cover, and then turn on the engine. Test the new headlight to make sure it works before replacing the air intake duct or the washer tank and closing the hood.
   

Replacing the High-Beam Bulbs
1. 1

   Undo the clips on the air intake ducts using a screwdriver and remove the duct from the engine compartment ( drivers side bulb removal only.)
   

2. 2

   Loosen the secured clip on the washer tank with a screwdriver and slide the tank horizontally to allow easier access to the headlight assembly (passenger's side bulb removal only.)
   

3. 3

   Disconnect the headlight electrical connector and undo the assembly retaining spring.
   

4. 4

   Turn the headlight bulb counterclockwise and pull it out of the socket.
   

5. 5

   Reinstall the new bulb, replace the retaining spring and reconnect the electrical connector.
   

6. 6

   Test the new headlight to make sure it works before replacing the air intake duct or the washer tank and closing the hood.
   

Go get the engine light codes read at any autoparts store...they usually do it for free and post them here...then we'll continue

Below is a link for the wiring diagram you requested:

2002 Subaru Outback Wiring

get in behind headlight under hood and look for a central plug or screw for the headlight to remove to get to the bulb you will have to unplug the wiring to pull it out and a spring clip youll have to press in towards the centre of the globe to remove it

Test to see if you have voltage at the bulb connector in low beam position. I'd almost bet that if there is no voltage there for the low beams that you have a bad high/low switch.

there are individual fuses for each side headlamps,both are 15amp located in fuse box underhood,check em out

all you need to do is remove the clip holding the washer fluid neck filler, once this is out of the way you can access the big gray backing that should have two wires coming out of it. just twist in the direction indicated and remove the cap, now you have access to the back of the bulb, remove the wires attatched to it and remove the metal clip that holds the bulb in place. now just put the new one in. You will see a small tab on the round part of the bulb, below the glass, align it right in the slot and put the metal clip back on and put the wires back on and backing cap and washer filler cap. P.S do not touch the glass on the new bulb, the grease on your fingers will prematurely burn the bulb out.

check all grounds