ABS brake warning light comes on and then sometimes goes off and comes back again.What is it trying to tell me

 

Most likely it’s an issue with one of the wheel speed sensors. Depending on your truck there will be one sensor at each front wheel and either a single sensor on the rear diff or sensors at both rear wheels.

Start with a visual inspection of the wiring.

 

How can you tell if one is bad

 

Is it just the ABS light that’s coming on, or are you also seeing the red BRAKE warning light?

Check for codes in the ABS system. If you don’t have a code reader, Any national parts store that reads codes should be able to do it.

FYI, a code for a particular sensor does not necessarily mean the sensor is bad. On front wheel speed sensors in particular, it’s more frequently a loose wheel bearing that’s causing an erratic signal; but it could also be damaged wiring.

 

Yes the brake light also comes on at the same time and it's both intermittent the brakes are fine it's just annoying

 

Check the brake fluid in the reservoir. Low fluid can cause the red BRAKE light which will also cause the ABS to come on as the control module won’t allow ABS operation with low fluid.

If that’s good, get the codes read.