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ChevyTech · 08-12-2008, 10:51 AM

If the instrument panel brake indicator light is blinking check the RWAL system for trouble codes.

RWAL stands for REAR WHEEL ANTILOCK. RWAL was standard equipment starting in 1988 on full size trucks.

1988 and newer trucks of that body style that do not have 4 wheel ABS have RWAL.

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.

If the light is blinking the manual states you should still check the codes by turning the key on (engine not running) and put a jumper wire between terminal A and H of the ALDL. Count the brake light flashes.

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

If you have a code 10 that would be a brake switch circuit code.

A code 11 has to do with the speed sensor circuit – does the speedo work correctly?

What year is your truck?

08-12-2008, 10:51 AM	#2
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,620	Re: brake warning light If the instrument panel brake indicator light is blinking check the RWAL system for trouble codes. RWAL stands for REAR WHEEL ANTILOCK. RWAL was standard equipment starting in 1988 on full size trucks. 1988 and newer trucks of that body style that do not have 4 wheel ABS have RWAL. 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. If the light is blinking the manual states you should still check the codes by turning the key on (engine not running) and put a jumper wire between terminal A and H of the ALDL. Count the brake light flashes. If you get one long flash and 5 shorter flashes that is a code 6. If you have a code 10 that would be a brake switch circuit code. A code 11 has to do with the speed sensor circuit – does the speedo work correctly? What year is your truck?