When iturn my wheels to the left my atb light comes on, when i straighten out the wheel the light goes out , the light does not come on when i turn to the right, whats wrong?

One side of your ATB is damaged and needs to be repaired/replaced. Below will explain what this is and what it does.

The QUAIFE ATB differential is designed to prevent the complete loss of drive that occurs with a conventional differential when one wheel slips. Whilst requiring some torque in the slipping wheel, the QUAIFE unit is progressive in action but never locks - controlled power is transmitted to all the driving wheels. Ideally suited to high powered front wheel drive systems, QUAIFE ATB differentials are also used in rear and four wheel drive vehicles where optimum traction is required. Installation is identical to the normal differential with bearing pre-loads and pinion mesh being restored to the original manufacturers' settings. Servicing of the unit is simple as all gear pinions are free fitting and normal final drive lubrication oils are retained.

As engine power outputs increase ever further, the ability to utilize this extra performance becomes more important. Wheel spin may look spectacular, but such losses of traction waste time either from a standing start or exiting a bend, whether driving on the road, circuit, rally stage or drag strip. Fortunately, QUAIFE's patented Automatic Torque Biasing (ATB) Helical *** differentialis an effective, well-proven, low-cost solution.