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

hogrocket · 08-11-2008, 01:54 PM

Hello all,

My brake light on my 70 3/4 ton stays on all the time. This is a sudden incident. I can't find a wire going to the emergency brake to activate a light. Is their a switch down there? Any suggetions on what's causing to stay on all the sudden? I really appreciate your help. Thx. MM

myoldchevytruck · 08-11-2008, 02:55 PM

Don't have an answer but here's ttt for you. Maybe someone will see it before it fall off the 1st page. Good Luck

rambler · 08-11-2008, 03:02 PM

If I remember that light is not for the parking brake/ emergency brake. you may be loosing pressure in your brake system either front or rear, check your proporting valve I think that is where it connects.

myoldchevytruck · 08-11-2008, 03:12 PM

Quote:

Originally Posted by rambler

If I remember that light is not for the parking brake/ emergency brake. you may be loosing pressure in your brake system either front or rear, check your proporting valve I think that is where it connects.

Unless he has swapped to front disks, he should not have a proportioning valve. He would only have a distribution block for the F/R drums, even for the 3/4 ton. Disk brakes became available in 71'. That's what I have always understood. Please correct me if I've given the wrong info.

**truckdude239** · 08-11-2008, 03:21 PM

your low pressure sensor has tripped you are talking about the light int he dash not the rear brake lights right

cdowns · 08-11-2008, 04:47 PM

first thing to check is the fluid level in the master cyl second thing is to find the leak

Longhorn Man · 08-11-2008, 05:01 PM

While myoldchevytruck is technicly right, the info is still acurate.
The proportioning valve and distribution valve are both located in the same area, and both house the switch that is turning on the dash warning lamp.
It is sensing a Difference in pressure between the front system and the rear system.
Time to find the leak in your brake system.

Bus Ted Knuckle · 08-11-2008, 05:13 PM

Are you talking about the brake lights on the back of your truck, or the "brake" light on the dash?

rambler · 08-11-2008, 05:20 PM

so ol' rambler was correct, I just should have said.. check out the dohicky thing connected to the master cylinder!

hogrocket · 08-11-2008, 05:21 PM

Thanks all, I was referring to the dash warning light. I will check the fluid and for leaks and see if that fixes it. Thx for the input. MM

08-11-2008, 01:54 PM	#1
hogrocket Junior Member Join Date: Apr 2006 Location: San Diego Posts: 100	Brake light always on Hello all, My brake light on my 70 3/4 ton stays on all the time. This is a sudden incident. I can't find a wire going to the emergency brake to activate a light. Is their a switch down there? Any suggetions on what's causing to stay on all the sudden? I really appreciate your help. Thx. MM

08-11-2008, 02:55 PM	#2
myoldchevytruck Retired Air Force Veteran Join Date: Aug 2007 Location: Pembroke Pines, Florida 33024 Posts: 1,808	Re: Brake light always on Don't have an answer but here's ttt for you. Maybe someone will see it before it fall off the 1st page. Good Luck __________________ Harry 69' SWB Step Side 1/2 Ton w/68' Front Clip Swap from Leafs to Trailing Arms (Complete) Swap 6 Lug to 5 Lug (w/ Disk Brakes in Front) 3/6 Drop Help Support The Board Click Here For Information On How To Subscribe Krue's FAQ Page Vendors

08-11-2008, 03:02 PM	#3
rambler MOVE OVER Join Date: Jun 2002 Location: Warrensburg, MO Posts: 5,470	Re: Brake light always on If I remember that light is not for the parking brake/ emergency brake. you may be loosing pressure in your brake system either front or rear, check your proporting valve I think that is where it connects. __________________ No matter where you are..... There you are... Buckaroo Banzi Last edited by rambler; 08-11-2008 at 03:04 PM. Reason: brain fart

08-11-2008, 03:21 PM	#5
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,234	Re: Brake light always on your low pressure sensor has tripped you are talking about the light int he dash not the rear brake lights right __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

08-11-2008, 04:47 PM	#6
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Brake light always on first thing to check is the fluid level in the master cyl second thing is to find the leak __________________ 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

08-11-2008, 05:01 PM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Brake light always on While myoldchevytruck is technicly right, the info is still acurate. The proportioning valve and distribution valve are both located in the same area, and both house the switch that is turning on the dash warning lamp. It is sensing a Difference in pressure between the front system and the rear system. Time to find the leak in your brake system.

08-11-2008, 05:13 PM	#8
Bus Ted Knuckle Son of a gun Join Date: Jan 2007 Location: Hot Springs, Arkansas Posts: 1,636	Re: Brake light always on Are you talking about the brake lights on the back of your truck, or the "brake" light on the dash? __________________ Bill BEATERS ARE NEATER

08-11-2008, 05:20 PM	#9
rambler MOVE OVER Join Date: Jun 2002 Location: Warrensburg, MO Posts: 5,470	Re: Brake light always on so ol' rambler was correct, I just should have said.. check out the dohicky thing connected to the master cylinder! __________________ No matter where you are..... There you are... Buckaroo Banzi

08-11-2008, 05:21 PM	#10
hogrocket Junior Member Join Date: Apr 2006 Location: San Diego Posts: 100	Re: Brake light always on Thanks all, I was referring to the dash warning light. I will check the fluid and for leaks and see if that fixes it. Thx for the input. MM



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