safe to drive with yellow brake light?

[122838B]

Is it safe to drive with the yellow antilock brake light on? I have heard two versions. One is that the yellow light only means no antilock brakes but the car can be driven because it still has the regular brakes. Another version is that the yellow light probably means the accumulator is not working and this puts a lot of stress on the pump and can lead to more expensive repairs. Just what is the safety and correct practice if the yellow light comes on and stays on at all times?

[Jim]

If the yellow light is on but the red light is off that means the ABS is not working but the brakes will still be working and have power assist.

If the red light is on the pressure is low in the accumulator.

When the key is turned on the pressure switch sees low pressure and turns on the pump/motor building up 2600 pounds of pressure in the accumulator. The pressure switch sees this high pressure and shuts off the pump. Even with a totally shot accumulator the pump should still run and build up the pressure. In this condition because there is no nitrogen in the accumulator, when you step on the brake pedal once, the red light would probably come back on. If, when the key is on the red light stays on, and you have a hard pedal that means the pump/motor is not starting.

You can test how good your accumulator is by doing the brake tests at Reatta.net

If you can pump the brake pedal 3 or more times without the red light coming on your accumulator is OK. Less than that, your accumulator is weak and your pump is running more than it should. The car is still safe to drive as long as the red light goes out.

[Howard]

As Jim stated, when only the yellow light is on, there is no anti lock functon. You still have normal braking power, just the anti-lock is non functional. However, just as a check, I would test the red light as well. When you set the parking brake, does the red light turn on? If so, the bulb is not burnt out. Never drive the car when the red brake light remains on.