My father has a 1999 F150.

The ABS light is always on.

We tried to pull codes with his code reader, no codes.

Tried to ground the brown and black line to get codes, no flashes of the ABS light.

Could someone please tell me what this means?

Thanks.

 

Check the abs speed module on top of the rear differential. It goes bad all the time. I had the exact same problem with my 1999 f150 and I went to the local dealer and bought one for $20 . Took me 10 minutes to put in and the light is off.

Good Luck