The transmission overdrive relay often fails, preventing the transmission from shifting into overdrive. In some cases the Overdrive light may stay all the time or not come on at all. The relay is located behind the center console, just left of the glove box. Before replacing the relay it is crucial that the wire leading to the overdrive solenoid is inspected to ensure it isn't shorting out on the transmission case. Failure to check this may lead to a failure of a newly installed relay.