The first step is to diagnose if the problem is in the ABS system,or if it's an electrical gremlin that is manifesting itself in the warning light.
When is the last time ALL the fuses were changed. This should be done every seven years. These little ceramic fuses can look good, but be bad. Change all the fuses, then disconnect the battery overnight. If the light still comes on, we'll go to the next step.

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