my 1989 200Q's electric engine cooling fan sometimes will run for extremely long times after engine shutdown. I've owned the car for many years and realize it is normal for the fan to run for a time if needed after shutdown, but now it will run until the battery is too discharged to restart the engine, i.e. for periods exceeding 20 minutes, and this is autumn in Illinois. The repair shop has changed the aux. cooling fan relay, the fan control relay, and the aux. fan resistor. Obviously, they are changing parts in hopes of a fix without first identifying a faulty part, which technique may be appropriate for this kind of problem, but now I'm loosing faith.

Does anyone have an idea of what to look at next to fix this? Thanks, Larry