The clutch switch is a simple off-on between the solenoid and ground. If you ground the wire leading to the clutch switch, the motor should crank with the key. Other then the start circuit, the clutch switch shouldn't be involved in any other function unless you have cruise control, then it would be involved in disengaging the cruise. The clutch switch on a stick trans replaced the park-neutral switch on an automatic trans.

You can also jump from the battery post on the solenoid to the small wire going to the starter and the starter should crank, be sure the car is out of gear first though.

If your having other performance issues, I would look at the ignition switch and the bulkhead connector for corroded wire terminals. Gene