Just bought my first Dodge and when driving it home I realized (after the purchase) that the speedometer wasnt working. Pounded on the dash and it jumped up but not to nearly what I was travelling. Several more pounds on the dash and it inched up... basically it sticks and wont go up or down reliably without pounding the dash, though it would loosen up over time but hasnt. Since the dash pounding works dont think its in the wheel sensor... if I take the dash off can I get to anything? Spray electrical cleaner in it... suggestions???