The present invention relates to a system for use in motorized vehicles to provide a vehicle back-up alarm system, intended for mounting on a vehicle, that also incorporates an apparatus for detecting and alarming low battery conditions. Preferably incorporated into a main housing are the electronic components that perform power regulation, system control, voltage sensing, timing, alarm tone generation, sound emitting and, optionally, light emitting. The housing serves to securely fix and retain these components and to protect them from moisture and dirt. The circuitry is connected to the vehicle upon which it is installed by preferably three connection terminals situated on the housing. Distinctive tones and/or lamp sequences alert the operator and those by-standers within proximity to the vehicle to different alarm conditions.