I have a 2006 TB-LS V6. The rear wiper won't turn off even though the interior switch is in the off position. I am not sure if it's a wiring issue or a motor issue. Any thoughts?

I am getting ready to trade the car in and I don't know if it's worth spending the time or money to fix it beforehand. If I fix it before hand anyone know approximately how much it may be?

 

Question Before checking wiring or fuses Are you aware that there are three (3) positions on the On/Off toggle for rather wipers? Top is on. Bottom is intermittent. You have to find the third position middle position and that turns the back wiper off.