Brake light

[BOX CAR]

I have a 89 chevy pu brake light on dash flashs,it has plenty of fluid seems to have brakes but still makes me unsure

Box car

[Macgyver55]

Watch the flashes and see if there is a pattern to them. That vintage truck only had rear wheel anti lock brakes. I believe they would flash a code if there is a problem, but off hand I dont know the codes.

[BOX CAR]

Thanks Macgyver

The light flashes 12times,still scatching my head

Boxcar

[Macgyver55]

According to an old article I found, Codes 1, 11, & 12 indicate an ECU Malfunction on an RWAL system.

Check any fuses or connections first if you decide to pursue it but the brakes should still work normally (like a pre ABS system) but the antilock system wont function if the light is on.

[Jeremy airjer W]

This is a long shot but don't you have to ground the "A" and "H" terminals on the ALDL to get ABS codes. If the light flashes 12 times that is not a code 12. A code 12 would be one long flash and two short flashes. I may not be thinking old enough so take this with an advil! (I would have said a grain of salt but the advil will help with the headache you will have!! )

[Macgyver55]

This is a long shot but don't you have to ground the "A" and "H" terminals on the ALDL to get ABS codes.

Thats not a long shot, thats how its supposed to work. Maybe with a bad ECU it went into diagnostic mode on its own? Who knows... Either way its probably not something worth putting much time into, as the RWAL systems had plenty of issues on their own.

[Jeremy airjer W]

Is it possible that since there isn't an ABS light that the brake light flashes by default when there is a problem with the ABS to distinguish itself as an ABS problem from say a e-brake left on or low fluid?

[Macgyver55]

Possibly, but its been a long while since they used that system so I dont remember.

He said the fluid is full, and the e-brake usually keeps the light on steady.

I've heard of them flashing on their own, but never encountered it myself.

[Big Buck Buster]

Just unplug the ABS module next to the brake master cylinder to clear it. Plug it back in and check to see if brake light stays out. If you don't want to spend the time or money to fix it, just unplug the module and the light should stay off, and you will have just standard brake without RWAL.

[jeffreyd]

had the same issue with the rawl on a ford in the 80's found that the overdrive was going out and would cause the brakes to go out of rawl. if it stops no problem, mine went to the floor had to use e brake to keep from going thru light

NOTES:

DTC's 6, 9 and 10 will only turn the "BRAKE" lamp on while the fault exists. These are soft codes faults and can only be read with the Tech 1 scan tool.

Do not jump terminals "A" to "H" if the "BRAKE" lamp is not on. Jumping the terminals with the "BRAKE" lamp off will set a false DTC 9. This will turn the "BRAKE" lamp on and disable the antilock system.

1, 11, & 12 ECU Malfunction

2 Open Isolation Valve or Malfunctioning ECU

3 Open Dump Valve or ECU Malfunction

4 Grounded Antilock Valve Reset Switch

5 Eccessive Actuations of the Dump Valve

6 Erratic Speed Signal

7 Shorted Isolation Valve or Faulty ECU

8 Shorted Dump Valve or Faulty ECU

9 Open Circuit to Speed Signal

10 Brake Lamp Switch Circuit

13, 14 and 15 ECU Malfunction

[BOX CAR]

WEll guys I fix the problem sorta,battery went dead twice charged up battery, light went out. Battery went out again this time I charged it in the dark noticed glove box light was on been a week now no problems.

Thanks to everyone that replyed

BAT