Any auto electricians here....?

[esselte]

My missus has a Galaxy,the rear wiper has packed in...I've checked the fuse which is OK,I've taken the tailgate panel off and checked the voltages to the motor...there are 3 wires..Brown:Earth...Yellow/Black...this has 12v on it and Green/Black...this has 6v on it..these voltages don't change whether the wiper is turned on or not...I'm going to change the next easiest thing..the relay...I hope it's this and not the switch...anyone any other ideas...?