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

Imacarguytoo · 09-04-2008, 12:00 PM

I jumped in my 91 burban this morning and saw that the brake light stays on while driving. I checked the brake fluid its full. My brakes are fine. The e-brake isnt on. Anyone got any ideas?

**old Rusty C10** · 09-04-2008, 12:20 PM

under the dash by the brake pedal further up than the actual foot pressing thing you will find a brake light switch it is prolly bad they are about $8 in the auto parts store and is just a wire that plugs into a switch when you press the brake it pops out and the lights light up

72 CustomCamper · 09-04-2008, 11:05 PM

More than likely it's the ABS module under the hood. Both of my uncle's early 90's truck have had this happen...

Chuck

**N2TRUX** · 09-05-2008, 12:08 AM

Quote:

Originally Posted by 72 CustomCamper

More than likely it's the ABS module under the hood. Both of my uncle's early 90's truck have had this happen...Chuck

This is a good probability. Check the plug that goes in to the ABS box under the master cylinder. Clean and re-seat the connector. It may be a bad box, but it could be the connector too.

Imacarguytoo · 09-05-2008, 05:02 PM

ok Thanks guys. Stupid question. It wont hurt the brakes driving it like that will it?

72 CustomCamper · 09-05-2008, 11:32 PM

I won't hurt them, you just won't have rear ABS. My cousin unpluged the box on both his and my uncle's trucks and have been driving them like that for a few years...

Chuck

joe231 · 09-05-2008, 11:51 PM

91 should be RWAL (rear wheel anti-lock)
worthless IMHO, just unplug it.
my '90 K1500 had RWAL, but when it malfunctioned my brake light flashed.
i ran with the module unplugged for 5-6 years no problems

ChevyTech · 09-06-2008, 08:46 AM

If the truck does not have 4 wheel ABS, then it will have RWAL.

There are three brightness levels of the dash brake indicator light on RWAL equipped trucks.

Brightest – park brake
Medium – Combination valve (aka metering & proportioning valve)
Dim – RWAL System

Watch the light very closely and apply the parking brake. Did the light get brighter?

You can unplug the wire on the Combination valve to see if it is the cause on the light coming on.

The RWAL system can store trouble codes, but it is only capable of storing one code at a time.

You can retrieve RWAL codes without a scan tool.

To retrieve RWAL codes connect a jumper wire between terminal H and terminal A of the ALDL connector with the key on (engine not running). Watch the dash brake lamp and count the blinks. Sometimes RWAL system send out a phantom blink before the code blinks start. It can take up to 20 seconds for the code to start coming out.

Checking the code with this method can set a false code 9. Checking for a code when no code is present sets a code 9.

You can clear the code by removing the fuse for 10 seconds then reinstalling it. The fuse should be labeled STOP/HAZARD or BRAKE. Removing the RWAL fuse will not clear the code.

If you get one long flash and 5 shorter flashes that is a code 6.

On trucks built after Aug 1994 a scanner is required to retrieve codes 6,9,10

This site tells how to read your codes.
http://autorepair.about.com/library/faqs/bl929g.htm

This site has general information about RWAL.
http://www.babcox.com/editorial/tr/tr89850.htm

09-04-2008, 12:00 PM	#1
Imacarguytoo Registered User Join Date: Nov 2006 Location: Illinois Posts: 306	Brake light on I jumped in my 91 burban this morning and saw that the brake light stays on while driving. I checked the brake fluid its full. My brakes are fine. The e-brake isnt on. Anyone got any ideas? __________________ '67 C20 Lwb 350 4-Speed '01 Chrysler Concorde LXI (wifes ride) '91 Gmc Suburban 3/4 2wd 454 Tbi '51 Jeep Cj3a "Willys" 350 V8

09-04-2008, 12:20 PM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: Brake light on under the dash by the brake pedal further up than the actual foot pressing thing you will find a brake light switch it is prolly bad they are about $8 in the auto parts store and is just a wire that plugs into a switch when you press the brake it pops out and the lights light up __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

09-04-2008, 11:05 PM	#3
72 CustomCamper huh ??? Join Date: Nov 2002 Location: Fredericksburg,Va. Posts: 3,368	Re: Brake light on More than likely it's the ABS module under the hood. Both of my uncle's early 90's truck have had this happen... Chuck __________________ 90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!"

09-05-2008, 05:02 PM	#5
Imacarguytoo Registered User Join Date: Nov 2006 Location: Illinois Posts: 306	Re: Brake light on ok Thanks guys. Stupid question. It wont hurt the brakes driving it like that will it? __________________ '67 C20 Lwb 350 4-Speed '01 Chrysler Concorde LXI (wifes ride) '91 Gmc Suburban 3/4 2wd 454 Tbi '51 Jeep Cj3a "Willys" 350 V8

09-05-2008, 11:32 PM	#6
72 CustomCamper huh ??? Join Date: Nov 2002 Location: Fredericksburg,Va. Posts: 3,368	Re: Brake light on I won't hurt them, you just won't have rear ABS. My cousin unpluged the box on both his and my uncle's trucks and have been driving them like that for a few years... Chuck __________________ 90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!"

09-05-2008, 11:51 PM	#7
joe231 Registered User Join Date: Dec 2007 Location: Palmer, Alaska Posts: 13,821	Re: Brake light on 91 should be RWAL (rear wheel anti-lock) worthless IMHO, just unplug it. my '90 K1500 had RWAL, but when it malfunctioned my brake light flashed. i ran with the module unplugged for 5-6 years no problems __________________ *CHEVY ONLY*

09-06-2008, 08:46 AM	#8
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,621	Re: Brake light on If the truck does not have 4 wheel ABS, then it will have RWAL. There are three brightness levels of the dash brake indicator light on RWAL equipped trucks. Brightest – park brake Medium – Combination valve (aka metering & proportioning valve) Dim – RWAL System Watch the light very closely and apply the parking brake. Did the light get brighter? You can unplug the wire on the Combination valve to see if it is the cause on the light coming on. The RWAL system can store trouble codes, but it is only capable of storing one code at a time. You can retrieve RWAL codes without a scan tool. To retrieve RWAL codes connect a jumper wire between terminal H and terminal A of the ALDL connector with the key on (engine not running). Watch the dash brake lamp and count the blinks. Sometimes RWAL system send out a phantom blink before the code blinks start. It can take up to 20 seconds for the code to start coming out. Checking the code with this method can set a false code 9. Checking for a code when no code is present sets a code 9. You can clear the code by removing the fuse for 10 seconds then reinstalling it. The fuse should be labeled STOP/HAZARD or BRAKE. Removing the RWAL fuse will not clear the code. If you get one long flash and 5 shorter flashes that is a code 6. On trucks built after Aug 1994 a scanner is required to retrieve codes 6,9,10 This site tells how to read your codes. http://autorepair.about.com/library/faqs/bl929g.htm This site has general information about RWAL. http://www.babcox.com/editorial/tr/tr89850.htm



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