Here are the two schematics:
The 90-92 MY...
The 93-95 MY...
The common problem with the 90-92 circuit is the relay at the clutch pedal: it carries
ALL of the starter current.
And, if the switch is turned to START prior to the clutch pedal being fully depressed (closing the clutch interlock switch in so doing) OR releasing the clutch pedal from the fully depressed position while the ignition switch is yet in the START position...will hasten the eventual failure of the switch.
Eventually, the starter will need servicing; the internal solenoid contacts, primarily. If there is a strong "CLICK" sound at the starter when the key is turned, but there is no start, chances are the high-current contact ring and/or the brushes need servicing (replacement). There are other potential issues with the starter too, but with the (loud) "CLICK" one can usually be sure there is a problem with the starter IF all the battery connections are or have been cleaned, of course.
Going back to the clutch pedal safety switch: The issue on the pre-93s is current load at the clutch pedal safety interlock relay: it is relatively high, and it results in arching - especially if the (clutch) is not fully engaged when the key is in the START position. Always making sure the pedal is fully depressed
before turning the ignition switch to START will significantly reduce internal arching/failure of the (clutch pedal) safety switch.
This problem was addressed in the 93+ MY cars (see schematics). However, the 90-92 MY cars can be retro'ed by inserting another relay between the clutch pedal switch and the starter (see below), OR eliminating the clutch safety switch altogether (by-pass).
Auxiliary clutch solenoid relay:
