I am thoroughly confused. This is the on/off switch for the brake lights? When the pedal is not being stepped on, the switch is open preventing voltage to the lights, also called normally open. When the pedal is stepped on, the switch closes and allows the current to flow through the lights, momentarily closed. In the open state, the resistance is Infinite, in the closed state, the resistance is zero. Shaffer - verify the ohm meter is functioning correctly, test it by itself, leads apart should read infinite, leads touching should read zero. Then test the switch. whatever reading the meter gets by itself, should be the same as with the switch. Some meters have indicators other than infinite, and there may be a few ohm resistance between the leads, ymmv.
The "normally" part means what condition the switch is in BEFORE it is activated. This switch is activated most of the time when, as Denny says, pedal up, not pushing on pedal. But when the pedal is pushed the switch is allowed to spring to it's "normal", as in: on the bench, nothing acting on it, position. Which in this case is ON or "closed". So it is a "normally on", referred to as a "normally closed" momentary switch. It's a little confusing. When this brake switch is in it's normal position, it is in the electrically on position because it's contacts are closed. Normally closed (NC)
Example:
If you have a momentary push button switch, the button is always up. It's spring loaded, that's the momentary part.
If you hold it down, it can do two things. Turn on or turn off, a circuit. The naming convention goes by what it does when button is up, not being activated, not being acted upon. Being held up by it's internal spring. It's "normal" circuit mode.
The analog meter has infinity, meaning OPEN circuit as you said. The digital has a 1 or OL, meaning Open Loop, open circuit. Any ohmage reading or beep is closed loop or circuit has continuity. I don't know what the resistance of switch contacts is. I don't know what scale/range he is using. Milliohms? So 300 somethings is continuity. During testing of the meter itself, some meters will register zero when the two leads are touched, some will read the resistance of the leads if the scale is proper and it's a good meter. Reading zero is actually saying it sees continuity but not measureable because "I'm a cheap unit". Testing an actual component should always show some reading. Not zero. Or should beep, or show a reading and beep, depending on the meter.
Some multimeters have a continuity setting, some don't. Some have a buzzer, some don't. On some you just use the ohm section and select the lowest range so as to detect some ohms (continuity).
Some are designed to actually measure ohms and/or also to find the other end of a wire in a harness by listening for the buzz/beep.
You have to know what mode you are in. If you have an old style analog or new style digital meter and read the instructions.
Now I'm the one making it more complicated
Man, I gotta get off this one quick............ Oh hey, it's also a single pole, single throw
