A lighted exterior rearview mirror system includes an exterior rearview mirror assembly including a reflective element and an electrically-operable actuator. The exterior rearview mirror assembly includes a breakaway joint assembly. The reflective element has an electrically powered heater operable to remove ice or dew from the reflective element. The exterior rearview mirror assembly includes a turn signal indicator lamp that has a light source and a lens. The lamp is included in the exterior rearview mirror assembly and unaffected by operation of the actuator. The breakaway joint assembly includes a wire-way through which a wire cable passes. The wire cable includes wires for operating the actuator, the heater and the lamp. The lens of the lamp has a portion that faces rearward of the vehicle and a portion that wraps around an outward side of a casing of the exterior rearview mirror assembly.