Vehicle alarm apparatus

Claim 1

For use in a vehicle having a battery connected in circuit with a horn means operated by a normally open horn switch, with a first vehicle accessory component connected by a first existing vehicle circuit directly to ground and having a normally open operating switch connected between said first component and a terminal post of said battery, with a second vehicle accessory component connected by a second existing vehicle circuit directly to said battery terminal and having a normally open operating switch connected between said second component and ground, and with a third vehicle accessory component having a casing thereof connected by a third existing vehicle circuit to ground; the improvement comprising an alarm device having a plurality of connecting points, and a plurality of lead lines formed with selectively attachable means connected, respectively, to said horn means circuit, to said first existing vehicle circuit at a point between said first accessory component and said operating switch therefor, to said second existing vehicle circuit at a point between said second accessory component and said operating switch therefor, and to said third existing vehicle circuit at a point between said third electrical component and grounds, said alarm device including control circuit means operable to close an operating circuit between said battery and said horn in response to a first full voltage circuit condition when said operating switch for said first component is closed, in response to a grounded circuit condition when said operating switch for said second component is closed, or in response to an open circuit condition when said circuit between said third electrical component and ground is broken.