The cooling fan relay turns on both cooling fans on the radiator. When the relay goes bad, only one fan turns on and at a lower speed (due to a resistor). Check out the wiring diagram...
http://www.pelicanparts.com/944/electrical/944_84_AC_2.jpg
This post makes a good point; troubleshoot a problem and you might find out it's an "easy" fix. Although, if both cooling fans are working properly then it is not a relay problem.