[Vortec350S10]

Man you must have the oldest S10 ever! That proves how long S10's can last! Seriously though I'm not sure on this but it might be on the drivers side inner fender next to the fuel pump relay or if not there I guess it could be under the dash somewhere. Try to follow the wire from the horn and see if it makes it through the firewall, then you know its on the inside somewhere. If I remember right I the wire should be green.