I hasd a similar problem with a 1990 Camaro. My carpet was wet from a leaking heater core. Smell the carpet where it is wet. Does it smell like antifreeze or is it the color of antifreeze? If so nyou have a bad or leaking heater core. Good Luck
have your heater core checked its probually leaking
It's either stopped up (no heat) or leaking. If leaking you will smell antifreeze (sweet sickening smell) and it might fog up your windshield with the defroster on. Leaking alot, the carpet is wet. Keep an eye on the antifreeze level.
the heater core is leaking it is located in the duct work under the dash
Could be your heater core leaking - stick your fingers under the front edge of the carpet in the right front passenger area and see if its damp (caution : don't lick your fingers afterwards )
under the carpet.
Heater box drain It is just below the heater hose conections, If the heater core leaks it drains the coolant outside to keep the carpet dry.
chances are the heater core is bad if it is leaking antifreeze keep a eye on youre level of fluid in your radiator, The 2005 and other model Subaru's have a tube drain for the A/C evaporator and that tube gets plugged up with dirt or other debris and causes it to backup and drain onto the passenger carpet , your Subaru dealer should have a service bulletin on this and remedy the problem.
Most likely it's a ruptured heater core, leaking coolant. But before you replace the heater core, check the connections outside the firewall. Sometimes a leaky connection will drip to the inside... but don't expect it; it doesn't happen often.
I hate it when things like this happen, so no longer do any auto repairs in the living room. It's better to use a room with an antifreeze colored carpet.
For a large area, remove the carpet from the vehicle, clean with a good carpet cleaner, allow to dry thoroughly, reinstall carpet. For a small area, clean with a good carpet cleaner and allow to dry thoroughly.
it is under the carpet on the passenger side,