Ross wrote:
If the governor switch is dirty, or the lockout switch, the relay will receive no signal telling the overdrive to operate. You can check the rest of the overdrive by patching a wire onto the relay at the same terminal you used to test it previously. Bring that wire inside the car and go for a drive. When you reach 25 or so ground that wire on some convenient screw or door handle and the car should go into OD when you let off the gas.