Brake warning light, The quest for success continues Options

[PaIsa]

So I am back trying to get my brake warning light to work properly. The situation before I started searching for the solution was the following:

Brake warning light was always blinking whatever the car condition. Blinked with the ignition ON. Blinked with the engine running and hand brake applied (normal). Blinked with the engine running and hand brake removed. Blinked with the engine running, hand brake removed and MC wire disconnected. So basically, blinking all the time!

So I was investigating the emergency (hand) brake wiring. Remove the seats, center console, etc. Looked at the emergency brake switch and seemed to work OK. There was a contact (closed circuit) when the switch was in position where the emergency brake would be applied and no contact (open circuit) when the hand brake would be removed. Looked on the wiring for evidence of short to ground but was not able to find anything. The wire goes in the center tunnel and is accesible until the shifter where rather then following the main wiring harness and the speedo cable, it goes under and God knows where it goes!! So I was not able to follow it all the way.

Now I have some disconnected wires near the brake fluid reservoir (already a thread on this trying to understand where these should go). The wires are brown-white and brown-white connected with a brown wire. The brown-white wire that is connected with the brown wire is cut.

So after I reassemble the emergency brake wiring, I did some test again.

Ignition ON, the brake light comes ON. Whit the engine running, no more brake light blinking.

So now I tried with the cut wire (the one near the brake fluid reservoir) reconnected. Brake light blinking all the time. Disconnect the wires, no more blinking when the engine is running.

I am lost. Even writing this I am not sure if I am right with the tests I did and the results I got.

Anyone has any advice? I looked at the wiring diagram, but not sure!!

I would like to have this working but don't want to go crazy with this!!

The car is a 1972.

[Ishley]

I have a 72... and I went out to my shop and looked at my wiring diagram.

The wire that goes to the switch for the parking brake is brown/white. Any wire in the loom that has brown is a ground... the white tells you that it is a switched ground.

When the parking brake is up and the switch is not depressed... the circuit is closed and the light has a ground... and therefore illuminates (when the key is on). When the brake lever is down the switch is depressed and open... and the circuit is not closed and the light goes off. The switch completes the ground through the body of the switch to the chassis... another words it should be clean around there where it mounts...etc.

The two wires hanging around the brake fluid reservoir where never used for the 914 that I know of... although I did see someone on a forum somewhere....get a switch cap I believe off a VW and made it work. It was a short run of cars that had these wires. I'm not sure what your doing with those two wires... but you may be closing a circuit and changing the behavior of how it works. I put heat shrink on both of them so they wouldn't short anything...and just left them disconnected. They shouldn't be plugged together... you would be closing the circuit and that could be your issue.

If you disconnect the wire (brown/white) going to the parking switch... you should be able to ground the wire to the chassis and the light with go on (with the key on of course). If it doesn't... you have a short in the wire. If you "unground" the wire... the light should go off... if it doesn't then the wire is grounding somewhere else... and you need to look for a short going upstream.

Test the switch separately... using a meter set for continuity... ground to the body of the switch and the other to the connector.

If all that is good... you have to make sure the switch/body is grounded well... or get a new switch.

Mine works perfectly with the 72 cantilevered hand brake handle... although I had to rig up a way to make sure the switch is depressed fully.... but that a different issue then you are having.

I found a wiring diagram online.... and I had it blown up... printed in color and laminated at a fedex /kinkos store. You should consider doing that so you can trace things.

I hope this helps.