wiring a volume control

WILL/can somebody PLEASE tell me how to wire a volume/dimmer switch?  I have three dimmer switches removed from an old limo's rear overhead panel's control module. They look just like volume control /variable/dimmer switches. My meter just took a dump, so I'm stuck.  I've wire a 12v bulb to a 12v battery to see if switch works by interupting circuit, by taking pos lead from battery to one of the three tabs that was soldered to the circuit board and taking another one of those tabs to one lead of the bulb and from the other bulb's lead to neg.side of battery. got nothing and tried other tab on switch, both tried reversing polarity, still nothing. bulb will not light up no matter how I wire it. All I can figure out  is that  why is there 3 tabs from switch in the first place? instead of just two?

Thanks, if somebody responds. Why I need this is because our old RCA TV in living room, where my stepdad kicks it, will be sitting there and then all ofa sudden the volume on tv shoots up so high that u can hardly stand it. And when this happens, the only way to stop it and lower volume, is to get up and manually push volume down button. The remote goes under a temporary spell from voodoo at same fng time!!! and is rendered useless!!! My stepfather has been disabled from injuries to both knees so its a real P.I.T.A. for him and us. Why not get TV fixed? Hard times due to his loss of job and my switching to from no job to any job, min. wage.  So I figured Why don't I install a switch, like a dimmer switch, to a small box that can be by his side, that is wired into one of the two speaker leads to adjust volume back down when this happens, and then when TV feels like going back down to normal level of volume, he then can turn it back up a little, from this switch, which stars out at a midway point of volume.