Norcal Vdubs


Northern California's Largest VW Enthusiasts Group
 
HomeCalendarFAQSearchMemberlistUsergroupsRegisterLog in

Share | 
 

 That lil red Brake warning light/button thing!!

View previous topic View next topic Go down 
AuthorMessage
LuvnVdubn

avatar

Posts : 76
Join date : 2012-04-13
Age : 35
Location : Citrus Heights

PostSubject: That lil red Brake warning light/button thing!!   Wed May 30, 2012 3:29 am

Does someone mind explaining to me the purpose of that light button thing. And how do I know if it is operating properly. And why the hell is it a button? or just seems like a button. Is it necessary? I know 10 years ago when i had my last beetle, there was a switch for the horn in it's place when I bought it. i never had brake issues though. I asked the dude at bugformance about the brake light button thing because when i bought this beetle it flickered a couple times the first time I drove her but haven't seen any life out of it since. He was like "ehhh don't worry about it, they are like that sometimes, no biggie" I asked him, "soooooo, if the light isn't functioning properly it's no big deal? Suspect " He said "Nope, just a bug thing"
I find it hard to believe there's no benefit to it functioning properly.
Back to top Go down
View user profile
TheAmazingDave



Posts : 85
Join date : 2012-05-02
Age : 34
Location : San Jose

PostSubject: Re: That lil red Brake warning light/button thing!!   Wed May 30, 2012 12:07 pm

The master cylinder is separated internally between the front and rear brakes. As a result, there's a pressure switch on the front and rear half of the cylinder.

The switches have 3 poles each, and are wired so that the normally closed contact runs to that brake warning light, and the normally open contact runs to the brake lights. The 1st pin is the brake lamp power input.

Now, imagine the rear brake hydraulics fail. When you step on the brakes, the front brake light switch will close, sending power to the input of the second brake light switch and out to the brake lights themselves. Since in our example the rear hydraulics failed, the rear switch does not close.

Now we have the front brake light switch feeding current to the rear switch, as well as the brake lights. Since the rear switch did not close due to pressure failure, instead of also sending current to the brake lights (remember, the normally closed contact connects to the warning light, not the brake lights) it will now illuminute the brake failure warning instead.

So with old switches, if you're just applying light brakes, it's defintely possible that one closed and one didn't, which would cause the light to illuminate breifly.

Since you know it works, and if that came on under heavy braking, you'd likely be looking at a failure.
Back to top Go down
View user profile
Breck

avatar

Posts : 814
Join date : 2012-01-12
Age : 104
Location : Citrus Heights

PostSubject: Re: That lil red Brake warning light/button thing!!   Wed May 30, 2012 1:31 pm

Hey Dave, I was thinking that you needed the three prong sender at the master... I do not have the light.
Back to top Go down
View user profile
Sponsored content




PostSubject: Re: That lil red Brake warning light/button thing!!   

Back to top Go down
 
That lil red Brake warning light/button thing!!
View previous topic View next topic Back to top 
Page 1 of 1
 Similar topics
-
» Brake warning light permanently on.
» Brake Warning on 85 K100RS
» Brake light always on except when on park position
» Starter warning light
» Tyre Pressure Loss Warning Light

Permissions in this forum:You cannot reply to topics in this forum
Norcal Vdubs :: VW Tech and Chat-
Jump to: