An interior mirror system for a vehicle comprises a housing having an interior compartment and is adapted for releasable mounting to an interior surface of the vehicle. A first electrical component/accessory is disposed in the interior compartment of the housing. A rearview mirror including a rearview mirror element and at least a second electrical component/accessory is pivotally connected to the housing. The first electrical component/accessory comprises a rain sensor module manufactured separate from the manufacturing of the rearview mirror that includes the second electrical component/accessory. The rain sensor module is received in the housing in a manner that connects the module electrically to the vehicle.