My 91 DX would not crank.

The clue was on the driver's floormat. "Start" position did zip but turn off the radio, etc. as it should. I suspected the clutch interlock switch. The test was to be a gymnast and reach up up up under the dash and manually push in the interlock while turning the key with the gripping hand. Do be sure the CRX is in neutral and the parking brake set.

The floor had the clue I'd missed. The pedal arm has a hole in the upper end where the switch would hit. There should be a little rubber bumper in that hole, but it had succumbed to time, and fallen out in 2 pieces.

So what to do? Well two things:
Short term: take a 6" length of #24 stranded wire. Strip each end for 0.5". On the underdash panel, the 2nd fuse from the end is [bizarrely] wired between the interlock switch and the solenoid. Pull that fuse, wrap the wire over the tab, and reinstall. To start, set brake, check neutral, ignition ON, and touch wire to an adjacent fuse TOP, where there's a test hole.
VRoom.

The long term fix:
46505-SA5-000 is the Honda part number for a new "Clutch Pedal Stop Pad".... $5.00 from your favorite supplier.

Also:

46505-SA5-000 - Honda Parts Now

does not look correct to me. The switch must be depressed to crank; the petal to the floor does that. Ergo, the pedal extends above the pivot & the bumper is up there. That was how I felt it.

On the brake pedal, losing the bumper causes the brake lights to be always on. BTDTGTTS.

 

Two different kinds of switches, the brake switch is held off by the pin stopper, the CIS is turned on by hitting the pin stopper.

One is a normally open switch the other is a normally closed switch. 94