Brake light on - The 1947 - Present Chevrolet & GMC Truck Message Board Network

UltraBlue71 · 07-10-2009, 10:31 AM

My brake light came on, I checked fluid levels pulled the vaccum hose plugged it and tried to reset it but it wont go out, what else could be making this stay on?

**DANTIP** · 07-10-2009, 12:37 PM

Does our pedal feel solid or spongy? Have you done any brake work recently? Did you check the wheel cylinders and calipers for leaks?

UltraBlue71 · 07-10-2009, 01:12 PM

No, thats the heck of it they feel fine and are working good.

Longhorn Man · 07-10-2009, 01:46 PM

the light does not moniter fluid level, or vacume or parking brake, it only comes on if there is a pressure drop on one side of the system, or if the switch goes bad.

greasy68 · 07-10-2009, 03:50 PM

Longhorn is right. The light only activated when there is a pressure difference between the sides of the hydraulic circuit. I popped a wheel cylinder in the back and the light came on. My brakes did not feel all that bad until i replaced everything then I realized they were really that bad. My brake light stayed on until I finished bleeding all the lines. If there is air in the lines the light will come on during braking and go off when you let off. At least that is what mine did. Also check the wiring for the light. It may be causing the light to come on if the brakes are good.

UltraBlue71 · 07-13-2009, 01:53 PM

I'm gonna have to pull the wheels off, dangit, come to think of it I left my jackstands under my buddies 69 camaro!

72-c20 · 08-23-2009, 10:29 PM

I'm having the same "problem". the light is on all the time now, and the pedal is super hard.... after it first happened, the light went off, and braking went back to normal, but now it's on all the time..... no fluid leaks anywhere.

UltraBlue71 · 10-08-2009, 03:29 PM

Mines still doing it too, brake pedal feels fine, I got sick of looking at it and unplugged it, that'll make it go away

tim21391 · 10-08-2009, 04:03 PM

when mine used to do that something was out off alignment in the rear the people said who i took it to

Don Smith · 10-08-2009, 05:11 PM

I chased a problem with brake light on for months. Bled brakes numerous times, tried stabbing brakes hard, checked wiring to switch. Finally decided to try a switch off an old proportioning valve and it fixed it. Tested switch after I removed it and it confirmed it was a bad switch (off a brand new proportioning valve).

UltraBlue71 · 10-09-2009, 12:25 PM

Thanks Don, I'll check that

LONGHAIR · 10-09-2009, 01:38 PM

Quote:

Originally Posted by Don Smith

I chased a problem with brake light on for months. Bled brakes numerous times, tried stabbing brakes hard, checked wiring to switch. Finally decided to try a switch off an old proportioning valve and it fixed it. Tested switch after I removed it and it confirmed it was a bad switch (off a brand new proportioning valve).

That kind of thing happens quite often, I always check new parts. Just because it's new, doesn't mean it's any good. That's what warranty is for.

cdowns · 10-09-2009, 02:04 PM

might try bleeding the brakes the way they say in service manual with the pin clamped to keep things centered and prevent the lght being on

**VetteVet** · 10-09-2009, 08:17 PM

The light works because the switch grounds the circuit through the brown wire back to the light. Unplug the brown wire from the switch and if the light stays on the brown wire is shorted to ground and you'll have to find that. If the light goes out then the switch is grounded and it's either a bad switch or one of the other problems already mentioned.

07-10-2009, 10:31 AM	#1
UltraBlue71 Registered User Join Date: Feb 2009 Location: OKC OK Posts: 489	Brake light on My brake light came on, I checked fluid levels pulled the vaccum hose plugged it and tried to reset it but it wont go out, what else could be making this stay on? __________________ "You can put lipstick on a pig, sure it's pretty pig, but it's still just a PIG... 71 LWB

07-10-2009, 12:37 PM	#2
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,888	Re: Brake light on Does our pedal feel solid or spongy? Have you done any brake work recently? Did you check the wheel cylinders and calipers for leaks?

07-10-2009, 01:12 PM	#3
UltraBlue71 Registered User Join Date: Feb 2009 Location: OKC OK Posts: 489	Re: Brake light on No, thats the heck of it they feel fine and are working good. __________________ "You can put lipstick on a pig, sure it's pretty pig, but it's still just a PIG... 71 LWB

07-10-2009, 01:46 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Brake light on the light does not moniter fluid level, or vacume or parking brake, it only comes on if there is a pressure drop on one side of the system, or if the switch goes bad.

07-10-2009, 03:50 PM	#5
greasy68 Registered User Join Date: Jan 2008 Location: austin texas Posts: 202	Re: Brake light on Longhorn is right. The light only activated when there is a pressure difference between the sides of the hydraulic circuit. I popped a wheel cylinder in the back and the light came on. My brakes did not feel all that bad until i replaced everything then I realized they were really that bad. My brake light stayed on until I finished bleeding all the lines. If there is air in the lines the light will come on during braking and go off when you let off. At least that is what mine did. Also check the wiring for the light. It may be causing the light to come on if the brakes are good. __________________ Mike 68 C10 LWB midnight blue metallic 307ci, 700R4, HEI front discs, leaf spring rear tilt steering wheel, stock ride height, rally wheels, 2007 Dodge Charger(Hemi)

07-13-2009, 01:53 PM	#6
UltraBlue71 Registered User Join Date: Feb 2009 Location: OKC OK Posts: 489	Re: Brake light on I'm gonna have to pull the wheels off, dangit, come to think of it I left my jackstands under my buddies 69 camaro! __________________ "You can put lipstick on a pig, sure it's pretty pig, but it's still just a PIG... 71 LWB

08-23-2009, 10:29 PM	#7
72-c20 Packrat Join Date: May 2008 Location: Central Iowa Posts: 459	Re: Brake light on I'm having the same "problem". the light is on all the time now, and the pedal is super hard.... after it first happened, the light went off, and braking went back to normal, but now it's on all the time..... no fluid leaks anywhere. __________________ gone: --'07 Tahoe LTZ 4WD --'68 Firebird 400 Convertible gone: --'72 Chevy K20

10-08-2009, 03:29 PM	#8
UltraBlue71 Registered User Join Date: Feb 2009 Location: OKC OK Posts: 489	Re: Brake light on Mines still doing it too, brake pedal feels fine, I got sick of looking at it and unplugged it, that'll make it go away __________________ "You can put lipstick on a pig, sure it's pretty pig, but it's still just a PIG... 71 LWB

10-08-2009, 04:03 PM	#9
tim21391 Registered User Join Date: Jul 2007 Location: Salina, Kansas Posts: 1,998	Re: Brake light on when mine used to do that something was out off alignment in the rear the people said who i took it to __________________ 1972 C-10...402/400..flowmaster 40 series 1967 Mustang 347 stroker/C-4 1966 Mustang 289/3-speed 2013 Mustang V6/6speed w/300 ponies I may be 23, but i sure do knows 67-72s are sexy! Its not MPG its smiles per gallon! build started 11/25/08 build thread: http://67-72chevytrucks.com/vboard/s....php?p=2993796

10-08-2009, 05:11 PM	#10
Don Smith Registered User Join Date: Jul 2000 Location: Hampton, Ga, USA Posts: 217	Re: Brake light on I chased a problem with brake light on for months. Bled brakes numerous times, tried stabbing brakes hard, checked wiring to switch. Finally decided to try a switch off an old proportioning valve and it fixed it. Tested switch after I removed it and it confirmed it was a bad switch (off a brand new proportioning valve). __________________ 68 Short Stepside, 350, quadrajet, 700r4, 3:73 posi, power front discs, HEI, Factory Air, Tilt, Tach, accelerator cable instead of rod, sway bar. 96 Impala SS 97 Monte Carlo

10-09-2009, 12:25 PM	#11
UltraBlue71 Registered User Join Date: Feb 2009 Location: OKC OK Posts: 489	Re: Brake light on Thanks Don, I'll check that __________________ "You can put lipstick on a pig, sure it's pretty pig, but it's still just a PIG... 71 LWB

10-09-2009, 02:04 PM	#13
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Brake light on might try bleeding the brakes the way they say in service manual with the pin clamped to keep things centered and prevent the lght being on __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

10-09-2009, 08:17 PM	#14
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	Re: Brake light on The light works because the switch grounds the circuit through the brown wire back to the light. Unplug the brown wire from the switch and if the light stays on the brown wire is shorted to ground and you'll have to find that. If the light goes out then the switch is grounded and it's either a bad switch or one of the other problems already mentioned. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.



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