rear abs light

hey guys, my rear abs light on my dash stays on. a friend put the sensor in the rear end and another piece on the rail on the drivers side. it's like a cylinder. i bled the front and rear brakes but not the valve on the rail. it has a bleeder valve on it which i just noticed. you reckon thats my problem? thanks guys
bill

hey guys, my rear abs light on my dash stays on. a friend put the sensor in the rear end and another piece on the rail on the drivers side. it's like a cylinder. i bled the front and rear brakes but not the valve on the rail. it has a bleeder valve on it which i just noticed. you reckon thats my problem? thanks guys
bill
it's a 1987 ford f-150