How to Troubleshoot a Honda Civic Clutch Starter Switchby Robert Bayly
The Honda Civic, as with most modern cars, uses a clutch interlock switch that is similar to the neutral-safety switch on cars with automatic transmissions. Where a neutral-safety switch prevents the engine from starting unless the shifter is in Park or Neutral, the clutch interlock prevents the engine from starting unless the clutch is pushed in. If your Civic will not start when you push in the clutch, the switch may be bad. You can check the switch with an inexpensive test light in just a few minutes.
Park the Civic on a level, paved surface and set the parking brake. Shift the transmission into Neutral. Slide the driver's seat all the way back because you are going to have to lay on the floorboard so you can reach the interlock switch which is mounted on the top of the clutch pedal.
Move under the dash and find the interlock switch mounted on the top of the clutch pedal. It has two wires running to it. Clip the wire on the test light to a good ground. Insert the probe end of the test light into the back of the switch
Have an assistant turn the key to the "Start" position. While you insert the probe end of the test light into the back of the switch and touch the wires, one at a time. One wire will illuminate the test light, and the other will not. If nether illuminates the test light, the problem is elsewhere.
Push in on the clutch pedal while your assistant turns the key to the "Start" position. Test the wires again. If only one wire illuminates the test light, the switch is bad. If both wires illuminate, then the problem is elsewhere.