Brake light Options

[ruddyboys]

OK I have amost all my guage lights working, new problem is the brake light. This time I have the light socket but no wiring to it. Looking at the wiring diagram I see the one post of the socket has a brown/yellow wire from the master cylinder brake switch and the hand brake switch connected to it. I looked in the Haynes manual and it gives no view as to were the hand brake switch is any pics? The other socket terminal should have a Black/White/green wire connected to the Turn Signal switch, do I have to take off the sterring wheel to find the wire at this switch? It also says it connects to the Hazard Turn Signal Flasher, is that the Hazard switch?

[Spoke]

The parking brake and master cylinder switch are in parallel and if one of them goes on, the red light on the dash goes on. For the parking brake the light is a reminder and for the master cyclinder the light is for an error. Neither has anything to do with the brake lights on the back of the car.

Somewhere down by the brake pedal assembly there is a switch that operates the brake lights. This is the one you want to work with. Use your Haynes manual schematic to follow wires from the fuse box to the bulb.

In my Haynes for a 74, the power comes from fuse S9, runs on black/yellow wire to the stop light switch by the brake pedal, then on to the lights in the rear again with black/yellow wire.

Note: my Haynes manual shows both brake lights in 2 places. So your wiring may vary. It's not usual to see one simple element listed twice...

Start at S9 and measure 12V to ground (power on, may want to disconnect power to coil/points/electronic ignition to prevent burn out, or just run engine the whole time).

At the brake switch, measure one side 12V to ground, one side 0V. Press brake pedal, measure 12V to ground on both wires.

At bulb, with brake pedal depressed, measure 12V to ground. Check contact on inside of bulb socket for voltage.

With car off, check bulb socket to chassis for ground connection. Should measure near short circuit (1-5 ohms). If not, trace resistance from chassis to bulb socket to find ground resistance.

If any of above fails, you have isolated your issue. If OK, keep looking:

Check bulb for working filaments. This is the duh test. Either check in another vehicle and see both filaments working, or check resistance with volt-ohm meter. Terminal 1 to case and terminal 2 to case will check both filaments. Should be 10-20 ohms each. Open circuit means burnt out filament. Replace if burnt filament.


Spoke

[Spoke]

Oop. I re-read your post and I think I answered the wrong question. If you're looking for the parking brake/MC light it should be behind the gauges. Since it's not overly important to vehicle operation it may have been disconnected at some time and should be in the wiring mess behind the dash.

Spoke

[Dave_Darling]

Handbrake light switch is under the handbrake handle. The connection is broken when the handle presses down on the button. Similar (same?) part to the buttons that tell the interior light that the door is open.

The other switch for the blinkenlight for the brakes is on the master cylinder, under the car.

The "hazard turn signal flasher" is the flasher relay, on top of the fuse panel.

--DD

[2-OH!]

Ok, I'm gonna' take a shot at answering this one....Maybe...

As I read your post, you are trying to wire in the Brake Hazard light in the Multi-Gauge on the dash...

As Dave said, the switch for the handbrake is under the handle itself, mounted into the crossbeam under the front of the seat...After 30+ years, it may or may not work...Probably a good idea to remove, re-condition and re-install...It's real simple...

The wire coming from it going to the gauge is brown with a white stripe...The switch (under the handle) is there to complete the circuit by making or breaking the "Ground" side of the circuit...In the rats nest up behind the gauge, it should join up with the Brown/Yellow (or white) wire from the master cylinder...They should be spliced together and then go to one side of the bulb...

In the rats nest, there should also be a Black/White/Green stripe wire from the turn signal/emergency flasher (same flasher unit for both and it's mounted behind the fuse panel)...(But I want to warn you, mine was just black/white)...That wire hooks to the other side of the bulb...Makes the light flash instead of solid on...If you want to have a solid on, then steal power from any Red/White wire in the rats nest...

2-OH!

No need to remove the steering wheel, except that it makes access to the gauges easier...