Brake warning light on

1998 TOYOTA COROLLA
110,000 MILES • 4 CYL • FWD • AUTOMATIC
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TOUCANF16
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The brake light comes on. The light is on when the parking brake is set and goes off as it should when the parking brake is released. While driving the brake light comes on, but the light will extinguish after braking to a stop. The light will then come back on about 5-10 seconds after accelerating from a stop. The fluid level is fine and the power boost seems normal. I have a video I can send of this if would help your diagnosis.
Mar 11, 2010 at 6:41 PM
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CARADIODOC
  • ASE Certified Mechanic
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  • ASE Certified Mechanic
You were correct to check the fluid level. The reservoir has one of three switches that will turn on the warning light. The second most common is the parking brake. When the light turns on again, pull the pedal up with your toes, or push the handle down for vehicles with the pull-handle between the seats. If the light goes off, the main parking brake cable is stretched and must be adjusted, (more common if you use the parking brake a lot), or one of the rear cables is sticking and not fully retracting under normal return spring pressure. This is more common when the parking brake isn't used very often.

caradiodoc
Mar 29, 2021 at 10:19 AM
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TOUCANF16
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The light works as it should with regards to the parking brake. And, like I said, the fluid level is full. Can I send a video of the occurance to help diagnose the problem? The light will be on while driving, it will go out after coming to a stop and will stay out while stopped, then the light will come back on about 5-10 seconds after releasing the brake pedal and accelerating from a stop.
Mar 29, 2021 at 10:19 AM
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CARADIODOC
  • ASE Certified Mechanic
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  • ASE Certified Mechanic
Your description is dandy. The only other switch is part of the combination valve near the master cylinder. It turns on when there is a leak in one half of the hydraulic system. Normally the light turns WHILE you're pressing the brake pedal, but if it tripped recently, it can do what you're describing.

Before you go searching for that switch, and assumming nothing changes when you play with the parking brake, unplug the switch from the master cylinder reservoir while the light is staying on. If the light goes out, if the fluid isn't low, check the styrofoam float to see if it's sinking.

caradiodoc
Mar 29, 2021 at 10:19 AM
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