A switch assembly module for controlling operation of a vehicle lamp includes a photocell integrated within the module housing to allow a controller to automatically switch the lamp on or off depending on detected ambient level. A manual switch is provided on a faceplate of the housing to allow disabling of the automatic operation feature. A manual switch can also be provided to allow variable dimming of the lamp. Integration of the photocell into the switch assembly module eliminates the need for separate instrument panel wiring to the photocell, while reducing wiring harness complexity by allowing the same harness and connector to be used with a module not having the photocell integrated therein.