This is a replacement speed control card for a Hillbilly Golf Trolley. 

The classic symptoms of a trolley that requires a new speed control unit are:

• The trolley will only go at one speed, usually full speed 
• The trolley is dead and a clicking noise may be heard

If the polarity has been reversed (ie a battery has been connected to the trolley 'red to black' and 'black to red') then 99% of the time this will damage the speed control card beyond repair.