85 380sl Anti-lock light

[Willy J]

Hi my anti-lock light just went on the other day. It gos on a minute or two after I start the car. The voltage is normal at the battery and the alternator charges fne. All the brake pads are in good shape. Where do I go from here. Would changing the brake fluid help. Thanks

[dmorrison]

The anit lock light is a computer test light. Not a physical part of the brake system. When the light comes on, the abs computer has some kind of failure. Either input or the main computer. It is common for the wires that go to the wheel sensors, in the wheel wells, to eventually crack and have a bad connectioin. They do a lot of flexing thoughout their life. I would start there. Use a volt/ohm meter to see if any of the wire connections are bad. Flex the wire while your doing this trying to duplicate the cars movement.
Second try replacing the fuse to the abs computer. If you have not replaced any fuses its a good time to do them all. Use the copper type fuses, not the alluminum ones.

Dave

[MrCjames]

Quick function tests that place you on the path to repairing the problem in timely manner:

1) Does your ABS (Anti-lock Brake System) light come on and stay with the igntion key?

OR

2) Does your ABS light come on when you begin to move the vehicle?

If 1 applies I suggest removing the cover on the ABS hydraulic unit and replacing the two relays.

If 2 applies look for a bad wheel speed sensor, most likely one of the fronts.

Sensor Tests: Resistance approx 1100 ohms (+/-10%), rotating wheel by hand-AC voltage output approx 700mV

Always