Brake indicator light stuck on!!

[Mean Green]

Alright guys i need some input, so tonight when i was leaving my girlfriends house, i noticed when i started my truck (94') the "BRAKE" indicator light came on and stayed on. So initially i checked to make sure that my parking brake didn't get accidentally bumped or something because that has happened in the past, anyhow that was fine. So i checked my pedal travel, and it is still nice and firm like always (maybe a hair more travel, but not really even a noticeable amount). The brakes still stopped really well, and seemed to function as normal. If i recall correctly i remember reading that the RWAL box can cause a problem like this? Any input and help would be REALLY appreciated guys!!

Info on the truck: 1994 GMC 2500 4X4, 350/4L60E, 124,*** miles. I replaced the brake lines from the firewall all the way to the rear axle last November, also bled the brakes, and put new fluid in at the same time, also all the brakes are in good condition.

Thanks ahead of time guys!

 

[theoutlaw]

I'd start by checking the wire connections. Do you have a factory service manual? It will tell you exactly how to diagnose and repair it.

 

[Mean Green]

I'd start by checking the wire connections. Do you have a factory service manual? It will tell you exactly how to diagnose and repair it.

I don't have the service manual for my 94'. It just came on tonight, tomorrow morning I'll pull it in the shop and attempt to diagnose the problem. I'm looking for common problems or ideas on what is most likely causing this. I just did a full inspection last weekend under the hood, and everything was up to par. But i will take another close look at all the connections into the RWAL box and master cylinder. Also I read somewhere that a dump valve will throw the light on also?

 

[Mean Green]

Alright so i pulled the code for the "(!)(P) BRAKE" light code and it was a code number 5 "Eccessive Actuations of the Dump Valve". I then unpluged the plugs out of the black RAWL box, and plugged them back into the box and the light went off and stayed off. Maybe all it took was just re setting the box by unplugging it.

 

[shortchevy]

Alright so i pulled the code for the "(!)(P) BRAKE" light code and it was a code number 5 "Eccessive Actuations of the Dump Valve". I then unpluged the plugs out of the black RAWL box, and plugged them back into the box and the light went off and stayed off. Maybe all it took was just re setting the box by unplugging it.

my 93 did this... I took off the RWAL, no more problems

 

[Swims350]

probably the dump valve going bad. Alot of guys just removed the box, that's what I did.

 

[shortchevy]

rear wheel abs is useless in my mind because chances are your fronts are already locked up and sliding by the time the rear abs kicks in.... this is a Wisconsin boys winter driving thoughts

 

[JJZ71]

What is the "RAWL or RWAL" box? My brake light comes on when I go over 35 MPH, then stays on until I shut off the truck. Would this help in my situation?

 

[Mean Green]

What is the "RAWL or RWAL" box? My brake light comes on when I go over 35 MPH, then stays on until I shut off the truck. Would this help in my situation?

The RWAL is the black box that is mounted horizontally on the master cylinder, RWAL stands for Rear Wheel Anti-Lock. You could try pulling the code while the brake light is ON by jumping the pins "A" and "H" on the OBD1 plug, and see what code it is throwing. That should tell you what is causing the light to come on in the dash.

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[JJZ71]

OK. Again I feel like a retard trying to keep up with you guys, but I'm learning!
The OBD1 is pictured above, what does OBD1 mean? I need simple terms! I'm taking notes!!!!
So would the OBD1 have pins A-L?