Truck won't start

I own an 85 toyota pick up. It has a 86 electrical system with a 95 engine. To date, this truck has run like a top until I got in the other day and turning the key nothing happened. That is to say, the starter did not turn or kick out. I had the starter tested and it is fine, I tested the starter relay and the neutral position switch. All the wiring checks out fine except for one That comes off the starter relay in the fuse box under the hood. This wire seems to be a ground for the coil side of the relay. In my books, it should go to a clutch /start switch that I can’t find. When I follow the wire it goes from the fuse box into the right side of the engine compartment into the fender area then runs toward the cab but I do not find its color combination going into the computer. I had this same problem with a 86 truck before and never found the problem . I would like to fix this one, though, so any help I could get I would truly appreciate. Thanks

Many times the switch is on the clutch pedal, look there and see if it is operational?