switch over valve

I've been reading a lot about this switchover valve, and my # 2 fuse is drawing enough current to kill the battery overnight, and this switch-over is connected to it. What does it look like on an 84 300? It must have a plug on it so I can see if it is what is causing the drain, and the sluggish take off.

Thanx

[engatwork]

It is mounted on the firewall behind the brake vacuum booster. Just unplug it and see if it resolves your problem. Do you have a wiring schematic?