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jalexquijano

E brake light dim on speedometer

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My ebrake light shows a little dim on the speedometer when the ebrake is off. Where should i check? It must be a bad ground somewhere.

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My guess would be that there is nothing electrical wrong with your e-brake light.

There is a little rubber shroud inside the speedo that is supposed to separate the e-brake light from the dash illumination lighting, and I suspect what you're seeing in your e-brake light is bleed over from your dash illumination bulbs.

The rubber shroud gets dry and brittle over time and maybe yours has deteriorated to the point where it's not sealing properly and it's allowing light to get where it doesn't belong. That combined with the fact that your speedo lights are very very very very very cornea burning bright....

So... Does the e-brake light glow go away when you turn off the dash illumination bulbs?

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Oh. In that case, forget about what I said.

If it's still glowing even with the dash lights completely off, it's not light bleed.

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Could be a grounding issue or a faulty proportioning valve. Or a faulty parking brake switch.

Why does it look like it's only lighting up half the "BRAKE" letters on the speedo? Like light is bleeding through from the left side. Or the bulb isn't inserted into the hole in the back of the speedo completely? Even if it's dim, I would expect it to light up the whole "BRAKE" indicator evenly.

Have you stuck a hand up there behind the speedo and gently wiggled stuff around to see what happens?

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I will stick the hand in.  I have never done this as this bulbs were replaced by the shop that installed the Air Conditioner when the dash was outside the car and i guees it was easier then. I simply hope not to break any wire , contact or the bulb when wiggling it. What would be your careful approach to this?

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Jajajaja i discovered that by removing the female plug from the proportionate valve under the brake booster the ebrake light on the speedometer did not appear at all.

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That most likely means you have problems with your brakes. One circuit is probably not working. Are your stopping distances longer than you think they should be?

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Any corrosion on metal parts on either connector you disconnected? 

Dennis

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Should i unscrew the center plug or sensor  marked as "1"  in the bottom drawing and clean it with a brush and electronic contact cleaner?

Brake proportioning.jpg

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Yes (it's a "bullet" connector and just pushes on, doesn't screw on).  And clean the inside of the connector that attaches to it also. 

Once you get the connection all cleaned up and reattached, that light will probably get brighter.  If it does, you have a problem with a brake circuit or a faulty pressure differential switch that will need to be replaced.  The switch inside completes a ground circuit for the warning light.  It can only do so if the shuttle inside is pushed out of it's neutral position by a brake circuit imbalance.  

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It looks like the electrical part is right, doesn't it?  The switch is doing its job, there seems to be a pressure differential.  The brakes might need bleeding.  Some people say that the 240Z switches need to be reset after the valve moves.

I could get my 280Z light to go off, when I had a problem, by pumping the brakes to remove the differential.  That was a clue, for me.

 

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On 10/3/2018 at 7:42 PM, Patcon said:

That most likely means you have problems with your brakes. One circuit is probably not working. Are your stopping distances longer than you think they should be?

Already cleaned both the female plug connetor and the tip of the male connector with a diamond grip terminal cleaner. Light still shows up a little dim when plugged. Should i get a wrench to clean the innards of the valve?

20181008_111237.jpg

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The 240z sensor does NOT have to be manually reset, it re-centers itself. My wheel cylinders were frozen with rust and the brake warning light would come on when the brakes were applied and go off when brake pedal released. I replaced the wheel cylinders and that cured the light coming on. The light works fine for the park brake. From the original description it sounds like the dim light is on all the time when the ignition is on regardless of the brakes being applied or not. My guess is a short in the sensor.

Edited by w3wilkes

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The sensor is what you referenced as "1" above. It's in the valve you provided the diagrams of. I know there's at least 1 other thread on that valve and how it works.

 

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Do you have a multimeter?  You can test the switch (what you are calling the sensor) by removing the wire and testing for continuity between the male bullet connector and ground (the thing you have circled in red in the picture above).  It should have NO continuity (open circuit) if the shuttle inside is centered properly. 

If it has any continuity then:

- There is an imbalance in the brake circuits

- The switch is stuck and off the neutral position

- The switch is defective

The fact that the light only illuminates when the wire is attached shows the "fault" comes from the switch itself, not a ground fault in the wire.

The Factory Service Manual advises against repairing this device - but that was back when they were still available from dealers.  I would probably source another one - failing that, There's a cross section picture above (Figure BR-12 Warning Light Switch)  that shows how it could be disassembled.

Edited by cgsheen1
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Okay. Now that i will have to bleed the brakes shouldnt i get a new set of brake pads and brake drums for the rear? Can you advise on this properly?

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4 minutes ago, jalexquijano said:

Okay. Now that i will have to bleed the brakes shouldnt i get a new set of brake pads and brake drums for the rear? Can you advise on this properly?

No need to change pads and rear brake shoes UNLESS they show significant wear or you notice a brake squeal (metal on metal) when applying brakes.  Don't make extra work for yourself.

Dennis

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23 minutes ago, jalexquijano said:

Bleeding only?

Only if you're tried, and eliminated, all the other suggestions like electrical grounding somewhere in the wiring.  Pads & shoes won't make the light come on unless they're very worn and brake fluid level is low.

Dennis

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As i previously informed i disconnected the female plug from the male middle switch of the proportioning valve and the low dimming light dissapeared.  I managed to spray electrical contact cleaner and brushed the tip of the male and female connectors and the light still shows up when plugging it back. What test should i perform now?

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