Brake Lights are Misbehaving - 69/70 Ghia Coupe

[toomdog]

Hi folks,
Some-time lurker and first time poster here. I'm sure this issue could apply to a beetle or a bus of the appropriate years, but I don't have one of those.
I've been searching everywhere I can think of with all the tools I can find and I haven't found any one else with this problem; figured I would toss it out here and see what comes back; please feel free to direct me if I'm in the wrong area here.

**EDIT** See bottom of this post for resolution!

The issue I am experiencing:
The brake lights are on any time the car is on.
If I move the brake pedal down a little bit, the brake lights turn off.
If I get further into the pedal, the brake lights come back on.
I've taken to tapping on my brakes three times to flash my lights at the guy behind me before I step on them. I use hand signals too, but I don't think anyone knows what those mean anymore.

The plot twist:
I got this car last August with the brake lights like this. I started driving it every day.
By the middle of October, maybe even September, the brake lights started behaving properly—Off when the pedal was up, On when it started moving down. And I hadn't changed anything.
This spring, when I started driving it again, the brake lights were still working correctly.
Then someone cut me off to make a right turn and I asked the brakes for everything they had (which was enough, thank God). Ever since then, the brake lights have reverted to their old behavior—ON/OFF/ON from top to bottom of pedal travel.

The details:
I have a brake warning light on my dashboard and three-prong pressure switches in my master cylinder. I have replaced the switches with brand new parts from JBugs. No noticeable change.
When we got the car, the pedal moved a long ways before it did anything, but the brakes were still good when you got there.
I have disks in front and drums in back. I adjusted my drum brake shoes for the first time about a week ago and it made a significant difference to pedal travel (I was getting 7 or 8 clicks out of the handbrake prior), but now I can start actually braking before my brake lights turn on.

For additional context, when I got the car, it had three radios installed, two of which worked, and I also had a couple 25A fuses in the fuse box and an AC radiator in the nose. The only instrument light that works is the gas gauge, but the gas gauge (sender?) doesn't work. I have not been able to successfully test my brake system warning lights and I don't know if it's a bad bulb, a faulty warning system, or there is just no power to that part of the dash.

What year is my car?
The subject says 69/70 Ghia because my chassis number starts with 1491, but my engine number starts with a B.
The schematics I have found for 1969 don't have the brake warning light on the dashboard like my car does.
The B engine numbers should all be 1600cc, but my engine is single ported. I saw one guy on YouTube mention they offered the 1600 with a single port option the first year of production.

In Closing:
Can you folks think of anything else I should check?
My best guess is there's a problem in the master cylinder?
My dad thinks there is a pressure differential between the cylinders that is setting off the warning light but that the warning light circuit is wired incorrectly into the brake lights.

RESOLUTION:
I switched polarity on one of the sensors and my brake lights work correctly now!
I went to try the simple test that I have seen suggested lots of places—touch one of the parallel post wires to the other on the same switch and the brake lights should go on.
I have two bundles of black, green, red wires coming from back around in the loom, no jumpers from one switch to the other; black and green are on parallel posts, red on the third.
I drove up on my ramps, got under the front, and pulled the black wire of the forward switch. The lights stayed on.
Replaced the black, pulled the green. The lights were off.
Replaced the green, moved to the rear switch and pulled the black. Lights were off.
Replaced the black and pulled the green. Lights were on... The wires on the rear switch behaved the opposite of the wires on the front switch.
I swapped the black and green wires on the rear switch and the lights stayed off. I stepped on the brake pedal and the lights came on... I thought I read that it doesn't matter which post you connect which wire to?

[jeffrey8164]

The switches are pressure activated so barring any potential miswire they should only come on when the pedal is depressed. Pull the wires off the switches and touch them together. The brake lights should light. So verify that part.
My only other thought would be to check the free play of the brake push rod on the pedal cluster. Maybe it’s just a little too tight causing pressure as things heat up while driving.
I have the chinesium switches from Jbugs as well and they’re not great. Mine activate my little B button when I press the brake but I’ve learned to like it. I can see when the brake lights come on.
_________________
Volkswagen!
Turning owners into mechanics since 1938.

“Let he that is without oil throw the first rod”
(Compression 8.7:1)

[dingerjunkie]

Another possibility...debris or corrosion from old(er) brake fluid and seal degradation holding just enough pressure at the switch-point to mess things up. When was the last time you did a full-system brake flush and bleed?

[PeteSC]

If it is a faulty switch there are other options that will work and don't involve trying to hit a jackpot with the cheap imported VW swtiches on the market.

I have a friend with a ground up bus resto, and he could not get his brake lights to work reliably. Switch after switch wouldn't fix it. He went with the Ross Wolf setup below that incorporates a Harley Davidson brake switch (it needs much less PSI to activate so the lights come on reliably and sooner).

https://rosswulf.com/shop/ols/products/vw-quick-brake-light-switch-conversion-kit

The other option is one I have on my Ghia that bypasses the switch completely. It's sold here on TS at the link below. I love mine - instant brake lights as soon as the pedal arm leaves the stop.

https://www.thesamba.com/vw/classifieds/detail.php?id=2140061

[toomdog]