Dash brake light on. Goes off when brake pedal pushed.

[mad.macs]

Well off on a 300 mile trip on Tues. My brake light on the dash has come on and will stay on until the brake pedal is pushed. If the Wbrake is applied the dash light stays on even if I push on the brakes. I looked it up in the Bentley a few months ago, but didn’t find anything specific, and it’s now at my buddy’s house, and I’ll go get it tomorrow.
It’s an 84 Riviera, so no fluid sensor in the cap, and the fluid level is just below Max. Pedal feels good, and I don’t have any issues stopping.
As I understand it, if the fault were in the hydraulic brake circuit, the light would be illuminated at all times.

I did jack the van up and confirmed that both front and rear brake hydraulic circuits apply pressure to the pads/calipers for the rear and the front.

Any assistance is appreciated!
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'84 Rivi Vanagon Auto Trans, Stock WBX

[Abscate]

Grab the manual for your Van from th eresources link above and read the s3ction on control scheme and lights

My recollection is the light is triggered on sensing pressure differences between the two master cylinder sensors....which only occurs during braking
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.ssS!

[B.O.B.Wanders]

The mechanical e-brake light switch on the floor might be stuck or something simple like that. Check that first.

If that is functioning normally, it could be the brake pressure switch issue. You can try removing the instrument cluster cover and unplugging them one at a time and see which one is the culprit - they usually don't fail at the same time.

Check to verify, but yours should be the three-prong switch. If one or the other is bad, make sure to get the ATE replacement. The cheaper ones are apparently junk. It is an easy fix and you don't lose much fluid at all if you are quick.
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83.5 WBX 2WD Assuan Brown Westy, B.O.B.

"It feels good to be lost in the right direction” - unknown

[mad.macs]

I’ll take another look at the brake switch, but with the brakes on, and the dash light extinguished pulling the e-brake and releasing it, does make the dash light go on and off, so I think the switch is working.

In other cars I have had, when there has been a fault due to pressure loss in one of the hydraulic circuits, the cylinder shuttles to one side and does not return to center until the issue is resolved.
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'84 Rivi Vanagon Auto Trans, Stock WBX

[74 Thing]

Check your fuses

[fxr]

(Noting you have an 84, like me)

One of your two SPDT brake light switches is faulty. Think of it like a house ceiling lamp that has two switches - if only one of those switches is operated, the light goes on and off. If they are both operated at the same time then the light can stay off all the time.

Best to replace both of them, they aren't that expensive. Keep the good one as a spare.
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Jim Crowther
1984 1.9l EJ22 Westy Wolfsburg Edition
Vespa GTS 300

[mad.macs]

So the parts store could only come up with one of them today. I tried it in both positions, and the symptom remains with no change.
Another switch is arriving tomorrow AM, I find the failure of two switches at the same time a little unlikely. I will install the second one when it arrives just in case.
The Bentley is not particularly helpful in diagnosing. The brake switches aren’t called out, other than their installation into the master cylinder.

Brakes and brake lights work, so I’ll probably need to let it ride this trip!
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'84 Rivi Vanagon Auto Trans, Stock WBX

[fxr]

[mad.macs]

I have both switches replaced now, and the problem persists. The brake lights on the rear are on constantly, but very dim. They turn bright when the brake pedal is pressed.
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'84 Rivi Vanagon Auto Trans, Stock WBX

[jlrftype7]

Do they go out if no switches are connected/wired?...(.The Dim- no -pedal illuminated situation)- If so, sounds like frayed wiring making a partial power/hot connection around-by-passing your switches. Not a short to ground, but a short to power that isn’t blowing any fuses since you still have the circuit path somewhat intact with the load out at the brake lights and not to ground.

[fxr]