Parking brake SWITCH troubleshooting

[Jonathan]

Hoping for a little help fellas, to get my parking brake switch (and thus the warning light in the instrument cluster) working again.

I believe the bulb to be good as the light comes on every now and again. We could circle back to this if other avenues don't go nowhere.

I optimistically had thought throwing in a new switch might do the trick, but after getting the new one in there tonight, no such luck. Old switch and new switch seem to have the same result... which is that the warning light does not come on regardless of the parking brake position.

The switch screws to the bracket of the parking brake handle with two screws. My screw heads were on the seat side (as opposed to the door side) so it was a little challenging to get them loose and put the new switch in, but I got it eventually. There is only one electrical connection to the switch, with a black wire with white stripe to its connector.

So, clearly there has to be a completed circuit somehow, but I'm not clear on what the other half of the circuit is? I can see a black (ground?) wire terminated at a bolt on that same bracket. I thought perhaps the connection wasn't good, so I took it off and reterminated, but it still doesn't make the little light go on.

Is this the right ground wire? and the other half of the circuit? Are there more wires hiding somewhere? I assume the switch completes the circuit when it's pressed, but not sure what the "open" position is? As a test, I tried to touch the ground wire directly to the switch connector and still nothing.

Anything else you can think of that I should look for? It really shouldn't be all that complicated :swear1:

[DMCMW Dave]

Bad contacts on the light bulb itself. I've honestly never seen any of the dash lights burn out, but we find them with dirty contacts all the time!

The alternate circuit to turn on that light is to connect the two pins of the plug that goes to the brake master cylinder cap together. If that makes the light (reliably) light up then you have a wiring problem near the brake handle, if not my guess is that the problem is in the cluster.

[David T]

The level switch on the brake master cylinder has a soft rubbery black center. If you press on it the warning light is supposed to light. Or you can lift the cap and switch out of the reservoir. Most likely a problem with the bulb or the PCB like dirty/loose connections.
David Teitelbaum

[Ron]

Is this the right ground wire? and the other half of the circuit? Are there more wires hiding somewhere? I assume the switch completes the circuit when it's pressed, but not sure what the "open" position is?Anything else you can think of that I should look for? It really shouldn't be all that complicated :swear1:
When the key is on, fuse #5 feeds one side of the Bulb +12V. The other side is connected to the Black-White stripe wire, which splits two ways. One to the terminal on the switch and one to the reservoir. (Grounding either turns the light on.) When you pull the handle, the switch connects to the solid Black wire, which goes to ground, so the light burns...

You might try grounding the Black-White wire with a test wire to Battery (-).
If it comes on the problem is from the switch terminal to ground...
If it doesn't, the bulb can be inspected/changed w/o removing the binnacle.

hope this helps...keep us updated.

[Jonathan]

Update:

So the light does not come on via the hand brake alone. Nor does it come on when I depress the centre "button" on the top of the parking brake reservoir. Now, having said that, my "button" seems to have burst up from underneath and there is oil to the touch when you go to press it down. Not sure what that means?

I did do a little reach around to go after the brake light from the drivers footwell. Well damn it if I always wanted to be able to palm a basketball, cause my hands are waaaay too big to try and get a grip on that bulb socket. I can feel the rectangular shape from the backside, and I read elsewhere that it needs to twist and unlock from the socket, but I can't get these silly opposing thumbs of mine to grab the thing and get it loose.

For fear of trying it for about 2 minutes longer and alleviating the stress of it all by hitting it with a hammer, I am going to admit defeat (damn big hands), and add this to my remove binnacle repairs list. So far I have this brake light bulb, the highbeams bulb, my odometer reset plunger replacement, and a loose connection somewhere that I believe is the cause of my occassionally bouncing tach needle.

I am only going to take the binnacle apart once I officially have the car stored for the winter, so with any luck I don't try this for at least another month.

STAY TUNED!!!