The radio doesn't work on a 1989 jaguar xj6?

can you clarify the question. Do you mean the radio will not power up or if it does is it looking for a Code? If it's looking for a code check to see if the 4 digit code is written on a piece of paper stuck to the underside of the engine bay hood. Other wise you will have to get it for a Jag dealer providiing you have the VIN and proof of ownership