I'm trying to sort out my wiring, fitting a six tacho etc. One thing I'm struggling on is the parking brake light. I've located the flasher relay



The wires out of the relay. Brown/red/blue+white/2xblack+white+green







When the Ign is switched on the brake light flashes as it should (parking brake switch not yet connected). When the the parking brake wire is grounded the light doesn't stop flashing.

try resetting the brake master cylinder switch ...
Andy

What I can't work out is when the hazards are switched on the brakelight flashes too?




a pic of the wiring on the back of the 2 indicators on the back of the speedo. Blue+white and black+white+green which I believe terminate at the flasher relay





and the brake light -ground brown and black+white+green






The parking brake switch has never been connected since I've owned the car and wiring isn't my forte anyway. Any suggestions gratefully receieved

Andy, I don't think I've got a switch on the master cylinder? I fitted a 19mm ages ago but can't remember there being any wiring down there. Did all the M/cylinders have a pressure switch?

Wouldmake sense though as the system is empty of brake fluid How do I reset the switch when it's refilled?

The parking brake switch is grounded when you pull on the brake lever. It is open when the handle is lowered into its resting position.

If you do not connect the wire or the switch isn't installed, the parking brake wire is open thus will not cause the flasher to flash.

If the brake light is always flashing, either the wire to the parking brake switch is touching the frame or the switch on the master cylinder has tripped. You can unplug (just for this test) the master cylinder switch to see if the brake light goes out.

If either of the master cylinder or parking brake switches is closed, the parking light will come on.

Not sure what you mean that the brake light flashes when the flashers are on. Is the brake light on only on occasions or on all the time?

Spoke

I just try the 4 ways in my car, the brake light will flash if the emergency brake
handle is pull up or it has a flase ground on it, if the brake cylinder is falsely grouned (dual brake cylinder function) wires on MC under car the light will also flash or it needs to be reset.

"Not sure what you mean that the brake light flashes when the flashers are on. Is the brake light on only on occasions or stays on all the time?"

Newbee to board here. Lots of good ideas and answers floating around and all ready put to use. Second Teener and this one I will appreciate!! First love was a 71 1.7 in '79. New love 72 (cleaned up by Camp914 7 yrs back) w/ 75 1.8 that runs way to rich. Lots of extras: 911 front end/16" fuches/mirrors/dash and 5 lug rear. My apoleges(sp?) to the Purist but hey it is all Porsche. And my eventual motor will be too!

As highlighted my brake lights stay on all the time when the ignition is turned on. Is this a sign of the master cylinder needing reset? All other lights work properly and I have double checked wiring at rear as well as cleaned ground at engine/cockpit firewall.

Thanks in advance for all thoughts ideas on brake lights and 1.8 running rich....

jkp

Spoke
[/quote]

That's some SERIOUSLY grotty wiring. Clean ALL the connections under there, find the bad ground, and you should get it fixed. The parking brake light, IIRC, doesn't flash. The Cap'n

I think I have found the trouble. I had replaced the 17mm with a 19mm master cylinder. The old cylinder had wiring for the pressurte switch but my 19mm does not have a place to fit the switch.
I guess i just connect the 2 pressure switch wires together.

Grotty?????????? hahahahaha

I haven't heard that in 20 years.

Thanks for making my day

My dictionary says it's spelled groady.....

.....but it's a 70s dictionary so you can't really count on anything.

The 19mm MC usually has a place for the switch, or comes with a switch in it. Often the switch only has one terminal on it, rather than the two of the original MC.

The switch works by shorting the wires together to turn the light on. With a one-terminal sender, the brown/yellow wire is connected, and the brown ground wire is taped up out of the way. If you hook the wires together, the light will flash any time the key is on...

--DD