Where to find the cigarette lighter fuse for a 2007 subaru imprezza?

SOURCE: cigarette lighter shorted out trying to get a penny out.

put a circit breaker in place of fuse. use a regular compass and run the compas around wiring and if compas moves thats where the short is within 6 inches. shorts create a magnetic feild

SOURCE: the interior lighting is not working after

Often the interior lights are looped on one circuit.
It only takes one bad connection to stop the 12v volts flowing. I would start with any connection that can be exposed to water or rust. Doors would be a good start.
Grab yourself a cheap multimeter and probe each connection (after removing the light bulb / lamp) for the presence of 12 volts DC.
If you have an electrical drawing use the 50/50 rule. ie check for power at the 50% point (halfway in the drawn circuit). If there is power at that point, check again at the next approximate 50% point ie downstream, continuing until you narrow down the area wit the problem. NOTE: If there is no power at the initial 50% point (the very first place you checked) work your way backwards (or upstream) in the circuit towards the fuse box, again using the same 50/50 rule.
If you are not confident, take it to a reputable automobile electrician.
Good luck,
Steve

SOURCE: 2007 Cadillac dts cigarette lighter fuse

You will find all the fuses under the back seat driver side.