Brake light switch wiring... what am i missing?

[Usudno]

So i have all of my wiring ran and connected. I have tail lights, running lights, turn signals, hazards as well. The only issues i still have is my brake lights and my high low selector switch. I'm using the dimmer switch from an early mustang mounted on the floor. it has 3 terminals and I'm not really sure how to wire it up.

As far as the brake lights.. I have the willwood pedal box and F5R supplied plunger style switch. The harness (ron francis MK4) has a connector that doesn't seem to fit the switch. The switch itself has 4 terminals on it and the connector on the harness has 2 wire.. Not sure how i need to run this but its the last thing from having me take the car home for my sons 9th bday this week..

Thanks for the help as always!

[Boydster]

Brake light switch... 2 terminals are normally closed, then open when stepping on the pedal. The other 2 are normally open, then close when stepping on the pedal. You want the 2nd pair for brake lights. The RF wiring book had me hooking up the wires the wrong way... they were always on until I stepped on the pedal. You want the normally open pair.

Dimmer switch: one terminal is an input from Headlight switch. The other 2 are output to lo beams on one side and hi beams on the other... doesn't matter how they are wired, you just have to get the input correct.

Both the dimmer and the brake switch should be easy to figure out with a simple ohm meter.

[Usudno]

I didn't have a meter handy but I tried both the orange and purple wires on both sets of terminals with no lighting... I will post some pictures of my wiring in the morning.

[brewha]

Boydster is correct on the brake lights. The RF book has the diagrams for the brakes on the wrong pair of connections. The brake switch connection is nearest to the brake lever. It takes some fine tuning moving the switch on the pedal assembly to get the brake lights on at the right time. The clutch safety switch will use the same connection on the other pedal.

[Usudno]

How can I test my brake lights without the switch?

[boat737]

Terminology is a little confused here. You should use the normally closed terminals, because the switch is technically in the normal state when the brake pedal is depressed, and the switch plunger is extended/out. When the brake pedal is released, and retracts back to the switch, the switch is now in the non-normal condition, that is, it is being pressed and activated, even though it is de-activating the brake light circuit. In other words, if the switch were laying on the work bench with no activity on it, the plunger is normally extended and the terminals are normally closed. Confusing as h-e-double hockey sticks, eh?

[boat737]

How can I test my brake lights without the switch?

Just put 12 volts to one of the two wires going to the switch. If they don't light, put it to the other wire. One of those wires goes to the brake lights. A Power Probe works like a champ in this case.

[Boydster]

Terminology is a little confused here. You should use the normally closed terminals, because the switch is technically in the normal state when the brake pedal is depressed, and the switch plunger is extended/out. When the brake pedal is released, and retracts back to the switch, the switch is now in the non-normal condition, that is, it is being pressed and activated, even though it is de-activating the brake light circuit. In other words, if the switch were laying on the work bench with no activity on it, the plunger is normally extended and the terminals are normally closed. Confusing as h-e-double hockey sticks, eh?

Nice catch! Technically you are very correct. But Normal becomes Not-Normal when installed in the Normal Position... normally.

[CraigS]

How can I test my brake lights without the switch?

Touch the two wires together. If they are still in a double plug, put a piece of wire or a paper clip so it touches both terminals at the same time.

[boat737]

Nice catch! Technically you are very correct. But Normal becomes Not-Normal when installed in the Normal Position... normally.

Thanks Boyd. As I say at my house, "Positively everything is absolutely perfectly abnormal." (I have a lot of sayings.)