A rearview mirror assembly of the present invention includes a circuit board disposed behind the mirror. The circuit board may be a flexible circuit board and may include an LED mounted to project light through a transparent window in the flexible circuit board and through the mirror. The flexible circuit board may function as a mirror heater and may include conductive paths for connection to the LED and/or electrodes of an electrochromic mirror. The LED may include an LED chip mounted directly on the circuit board and encapsulated thereon by an encapsulant.