Bypass it to determine if that is the problem or test with an ohmeter if you have specs.
The first clue would be,having voltage at the terminal of the switch, when the switch is turned on,the circuit does not energize.
Switch it with a known good one from a non critical circuit to see if it solves the problem.
By taking it off and testing it for resistance with a digital multimeter.
Use a jumper across the inertia switch if the fuel pump comes on-its defective
That is typically casued by a bad seat safety switch, a bad connection at the switch or a bad wire going to the switch.
Either the machine does not "know" or the clutch/brake switch is bad. Either way it is a safety switch
If your turn signal lights come on but do not flash, then the flasher relay is defective. If they will not come on at all then the fuse may be blown. If the fuse is good, then you may have a wiring problem. Rarely does the switch itself go bad but it is possible. The feel of the switch will sometimes tell you it is bad. If you do not feel it click when pulled then it is probably bad. It is just a matter of troubleshooting the problem.
It is important to know the symptoms of a part going bad. The signs of an ignition switch going bad is it overheating, no clicking when trying to start, the car has issues starting and running.
Switch could be bad or the schraeder valvee the switch screws into could be bad
If the brake light fuse is good and the brake light bulbs are good it's probably a faulty brake light switch.
Possibly bad wiper motor, bad park switch, or bad wiper switch. Electrical short also possible.
You can tell if your fuel pump shutoff switch is bad, if the fuel pump does not shut off when you flip the switch. You can also tell if the switch is bad by looking at the wire connections.