The most prosaic explanation is that something spilled there and the water soaked through the carpet.
ac drain stoped up or heater core bad
Under the carpet in the right rear of the trunk.
In the trunk, under the carpet.
Under the carpet in the floor of the trunk.
It is under the carpet in the trunk.
It is under the dash on the passenger side.It is under the dash on the passenger side.
Under the dash on the passenger side.Under the dash on the passenger side.
Under the dash on the passenger side.Under the dash on the passenger side.
under the carpet in the trunk
Check under the front passenger seat.Check under the front passenger seat.
Under the front passenger seat.Under the front passenger seat.
Under the front passenger seat