ec430

03 sl55 cooling fan is operating erratic and spins slow then speeds up and slows down then dies out after a few minutes as car get hot. I will remove it tomorrow to check it on bench but curious if anyone else has dealt with this problem? It spins freely and doesn't make any bearing noise when it is at full speed but is running much slower then our other later Sl55. Any suggestions? I see no relay for the fan and the fuse for the coolant fan is f49 according to fuse charts and a 5 amp fuse which is a light fuse to not have a relay.