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> How do you reset the master cylinder brake switch, The 2 wire type
913B
post Sep 5 2016, 08:30 PM
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The brake switch on my master cylinder has 2 wires. I didn't see any reset button. When I unplug the brown/white signal wire going to the brake light in the gauge. The brake light will respond accordingly to the hand brake and go out. Before it would stay lit all the time regardless if the handbrake was applied or released.

So the question is how do you reset the brake switch or do I need to bleed the brakes ??

The brake light was working fine until the transport company moved my vehicle. I think the driver may have applied the brakes too hard maybe (IMG:style_emoticons/default/confused24.gif)

Let me know you thoughts.

Thanks everyone ! (IMG:style_emoticons/default/driving.gif)
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Krieger
post Sep 5 2016, 09:36 PM
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The reset is on the left side of the master cylinder. You can get at it without lifting the car. Turn the steering wheel all the way to the right. Get a flashlight. It is a small rubber protusion maybe 5mm on the left side. Just push it back in. You also might want to check the switch under the handbrake. It is on the crossmember. It may be stuck, broken or corroded. It is also possible the handbrake is not making contact with the switch and is not pushing the switch down when you put the brake handle down. My gauge light flashes red when the e-brake handle is up.
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913B
post Sep 5 2016, 10:03 PM
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QUOTE(Krieger @ Sep 5 2016, 08:36 PM) *

The reset is on the left side of the master cylinder. You can get at it without lifting the car. Turn the steering wheel all the way to the right. Get a flashlight. It is a small rubber protusion maybe 5mm on the left side. Just push it back in. You also might want to check the switch under the handbrake. It is on the crossmember. It may be stuck, broken or corroded. It is also possible the handbrake is not making contact with the switch and is not pushing the switch down when you put the brake handle down. My gauge light flashes red when the e-brake handle is up.

Is it on the switch itself ?? I don't suppose someone has a pic ? I even took the wheel out and didn't see any switch though? I want to fix it so I can pass my vehicle inspection for my registration.
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913B
post Sep 5 2016, 10:06 PM
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QUOTE(Krieger @ Sep 5 2016, 08:36 PM) *

The reset is on the left side of the master cylinder. You can get at it without lifting the car. Turn the steering wheel all the way to the right. Get a flashlight. It is a small rubber protusion maybe 5mm on the left side. Just push it back in. You also might want to check the switch under the handbrake. It is on the crossmember. It may be stuck, broken or corroded. It is also possible the handbrake is not making contact with the switch and is not pushing the switch down when you put the brake handle down. My gauge light flashes red when the e-brake handle is up.

The handbrake part works fine. With the signal wire that goes to the gauge disconnected. The handbrake operates the brake light fine. Thanks for tip
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Krieger
post Sep 6 2016, 09:33 AM
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Post a pic of your master cylinder
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North Coast Jim
post Sep 6 2016, 12:02 PM
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QUOTE(porsche913b_sp @ Sep 5 2016, 10:30 PM) *

The brake switch on my master cylinder has 2 wires. I didn't see any reset button. When I unplug the brown/white signal wire going to the brake light in the gauge. The brake light will respond accordingly to the hand brake and go out. Before it would stay lit all the time regardless if the handbrake was applied or released.

So the question is how do you reset the brake switch or do I need to bleed the brakes ??

The brake light was working fine until the transport company moved my vehicle. I think the driver may have applied the brakes too hard maybe (IMG:style_emoticons/default/confused24.gif)

Let me know you thoughts.

Thanks everyone ! (IMG:style_emoticons/default/driving.gif)


Just reworked my entire brake system with help from PMB Performance. Replaced the master cylinder as well. I too had the persistent "brake" light flashing/alarm and didn't know how to remedy the situation. Was told by Eric at PMB that I needed to reset the switch. Since I had the car up on stands I could easily get to the master cylinder again. Removed the boot protecting the two electrical wires. Adjacent to the two electrical posts is the switch, not really a switch since all you have to do is push it in. It is only a protrudence of plastic and not easily recognized as a switch. Push on it while the key is turned to the on position. You will hear the cessation of the brake alarm. The brake light will stop blinking. Easy. I've had to do this twice now once with the car on the ground.
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Kansas 914
post Sep 6 2016, 12:12 PM
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It is the black "shaft" in this picture.

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913B
post Sep 6 2016, 01:07 PM
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I wish I had a pic of my switch the center part is like a plastic divider. It is slightly different design than yours (IMG:style_emoticons/default/sad.gif)
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913B
post Sep 8 2016, 09:36 PM
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So I have come to the conclusion there is no reset button on the early 2 wire brake switch.

I even tried reversing the connections, but no such luck,

The short term fix is leaving the brown/white signal wire unplugged from the switch. The brake light on the gauge will only be controlled by the hand brake lever.

The long term fix is next time I am under the vehicle. I'm going to swap out the switch with the single pole type with the reset switch.

That is my update for now.

(IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beerchug.gif)
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Garland
post Sep 8 2016, 10:20 PM
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I have the same concern, have left the one wire loose. I think the switch is bad. Going to replace it with a 2 pole switch.
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913B
post Sep 8 2016, 10:41 PM
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you want to switch to 2 pole ?? You mean to replace it with 1 pole with the reset button ?
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Garland
post Sep 8 2016, 11:36 PM
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QUOTE(Garland @ Sep 8 2016, 10:20 PM) *

I have the same concern, have left the one wire loose. I think the switch is bad. Going to replace it with a 2 pole switch.



I have 2pole now. With one wire unpluged.
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Dave_Darling
post Sep 9 2016, 09:55 AM
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I have a two-pole switch with a reset button...

My understanding is that the switches without reset buttons do not "latch", so that when the pressure balance is removed they turn off themselves.

Do you have a good photo of your switch?

--DD
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NoEcm
post Sep 9 2016, 10:35 PM
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I just installed a new single pole switch because the old one was leaking brake fluid.

The defective one had a little reset button you you could depress.

The new switch that I just installed does not have a reset button.


Pictured below is the defective switch that I purposely tripped for this thread. Push the little nub back in and the switch gets reset.

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913B
post Sep 11 2016, 04:50 PM
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Thanks everyone for the contributions. I want to see the reset sw on the 2 pole type if there is such a thing ?

(IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/smilie_pokal.gif)
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