Brake light on

[Imacarguytoo]

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]

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]

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]

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]

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

[72 CustomCamper]

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]

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]

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