How do I test the ignition switch?

[autiger]

I experienced four episodes where my 2001 SL1 5spd w/ 114K miles would not crank when I attempted to start the engine. No click, nothing. Read multiple threads/Haynes repair manual. Battery volt tested ok both w/ and w/o load, + lead from batt to solenoid tested ok, solenoid checked out ok using jumper lead from batt + to "s" terminal, and had reading of 16v reading at + lead to the starter motor term of the solenoid. How do I test (and what reading should I get) the purple ignition wire to the "s" terminal? Also, how do I check the Neutral start switch? Any other suggestions? Thanks!

[fdryer]

Simply disconnect the purple START wire from the starter solenoid. This ensures the starter won't engage. Now just measure the voltage from the purple wire to ground; the only time you'll see voltage on this wire is when the ignition key is turned to the START position. Have someone turn the ignition key as you measure for 12v on the wire. This should occur every time the key is held in the START position so cycle the ignition switch several times from the ON position to START, release the key and repeat. The voltage should appear every time and hold there as long as the ignition key is held in the START position. You've just verified the ignition switch and its reliability to do this every time. If you are satisfied that the ignition switch is fine, move on to what may be the problem, the starter.

Starters are more difficult to understand and troubleshoot unless you're very well experienced in car electrical systems. The starter requires tremendous amperage to turn over an engine, 50-150+ amps of welding current that places a premium on good battery cables and batteries. Knowing the age of the car or if the starter is original, replaced, and other essential information of the car's electrical system can isolate a starter problem. The large currents needed to run a starter motor wears away the starter brushes over time so knowing the age of the starter, mileage in general, and specifically if there are other sounds or lack of can determine if its the starter. A last ditch attempt to isolate a worn out starter is to bang the side of the starter with a 2x4 a few times; this 'realigns' the worn out starter brushes for another start and good enough to call it a worn out starter.

[madpogue]

There is no neutral safety switch. There's a switch that closes with the clutch pedal, on the floor/firewall. Easy place to test the START position of the key switch. Disconnect the clutch switch, and connect a voltmeter between the terminal on the yellow wire and a good ground. Turn the key to START. You should get battery voltage (12-13 VDC).

[dorisSL]

Originally Posted by madpogue

There is no neutral safety switch. There's a switch that closes with the clutch pedal, on the floor/firewall. Easy place to test the START position of the key switch. Disconnect the clutch switch, and connect a voltmeter between the terminal on the yellow wire and a good ground. Turn the key to START. You should get battery voltage (12-13 VDC).

or, disconnect the switch and jump the terminals on the harness with wire.

[madpogue]

Originally Posted by dorisSL

or, disconnect the switch and jump the terminals on the harness with wire.

That just bypasses the clutch switch. The OP wants to test the START contacts on the key switch.

[autiger]

Thanks, I'll test both and get back with my results