How to React if Your Car's Brake Light Comes On

Your brake light is on with no good reason... or so it seems. Have you been driving with the hand brake on? Are you low on brake fluid? If the answer is yes, heed our tips below.

Difficulty: Easy

Instructions

Things You'll Need:

• Brake Fluids

1. Check out your brake situation as soon as you can if the brake light goes on. You don't need to stop driving immediately.

2. Turn the engine off and open the hood.

3. To find the brake fluid reservoir (also called the "brake master cylinder"), look for a round black rubber cap about 2 to 4 inches in diameter that covers a plastic container. Imagine where your foot would be if it went all the way through the car toward the engine past your brake pedal. This is where you will almost always find the brake master cylinder.

4. Check the fine print on the rubber cap. It should say, "Use only DOT 4 (or 5 or 3) brake fluid."

5. Remove the cap. If the cap is dusty or dirty, wipe it off with a rag so no dirt particles fall into the reservoir.

6. Check what kind of brake fluid your car requires. This is indicated on the rubber brake reservoir cap and in the owner's manual. DOT 5 is the highest grade available right now and can be used in any system. If your car requires DOT 4, do not use DOT 3 or a lower-grade fluid. DOT stands for Department of Transportation.

7. Fill the reservoir with brake fluid up to the "full" line. If there is no "full" indicator, fill it to the top.

8. Put the cap back on and wipe up any spills.

9. Turn the car on and the light should be off.

10. Wait, you're not done yet! Now call your mechanic and make an appointment for a four-wheel brake inspection to find out why the brake fluid was so low.

11. Make an appointment for a brake check immediately if the light goes off but the pedal sinks to the floor.

Tips & Warnings

• The brake reservoir cap may say, "Only use brake fluid from a sealed container." This does not mean you must purchase a new bottle of brake fluid every time you want to add brake fluid. It's reminding you not to leave the bottle of brake fluid out in the open with the cap off, because particles of dust and dirt may get into the bottle, and dirt will cause problems with your braking system.
• Brake fluid is highly corrosive. Take care not to spill any on your clothes, and wash your hands if you get any on your skin.
• Try not to spill any brake fluid on the paint of your car, as it will mess up your paint job if you don't immediately wipe it off.

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[91preludesi]

on 12/19/2008 Thank you for updating this one and taking out the incorrect info.

[91preludesi]

on 9/6/2008 The eHow cars editor at it again with bad information. The very first sentence is wrong!! There are MORE than two reasons your brake light may come on. The two mentioned above, or it could be a faulty sensor, the sensor may be unplugged, or the float inside the resevior may be stuck to the bottom. All of these can turn on the light. Count 'em...that's FIVE...more than two. Take everything you read from the eHow cars editor with a grain of salt. I am trying to review all of their articles to give you correct information.

[drkknite]

on 12/6/2007 The classifaction of brake fluids is off as well, If your master cyclinder says to use DOT 3 use DOT 3, Not 4, Not 5. DOT 3&4 are polyglycol based fluids, DOT 5 is silicone based, mixing the two will result in an exspensive repair bill.

[exhako]

on 12/27/2007 My brake light goes on on winter times and off in summer, but the brakes operation is the same... good. Anyone have any idea why?

[eccguruva]

on 8/2/2007 Brake fluid should not be stored after opening, it is hygsuroscopic, which means it absorbs water, which can cause failure of the system. Since you don't have to change or add fluid very often, unless you have a serious problem (leak) then... its best to buy new, rather than store.

Also Several other causes exist for the brake warning light, such as air in the system, blockage, internal leake in the master cylinder, or change in viscosity of the fluid.