My car, from one moment to the other did not want to start, all electricity worked fine, but the starter motor would not make any noise.

So, the first thing what I did was test the starter motor itself. The way I did that was to put it in neutral (I have a manual) and connect the solenoid with the positive directly using a piece of metal. The starter started, so that was not the issue.

Second I tested the starter relay in the dash fuse box by testing for continuity between as indicated in the manual. Not the problem.

So, next I looked at the clutch interlock switch (also called faulty neutral switch (is for automatics) or at part stores the clutch starter safety switch). Instead of twisting myself in a pretzel, with someone else pushing the clutch, I just pulled out the plug, and connected it with a metal wire. if the car would start, it would mean that the switch was the problem. The car started.

So, I took the switch out, and before going to get a new part, I decided to just connect it and push it by hand to double check that it was broke. The car started.

So, I screwed it back in. No start.

Screwed it out again. Hand push -> start.

Then I remembered that the break light switch has a small piece of plastic and when it breaks, it leaves a hole for the switch, and it won't work. So, I look through the hole where the switch is normally, and indeed, a hole in the clutch pedal instead of a small piece of plastic.

So, this will be a penny repair, because all I have to do is glue a penny on top of the hole and the car should start again.

Because of the impossible position, I took a pencil, put some tape at the end to hold the penny, added glue and was able to tap it in place relatively easily.