The thermoswitch that controls the HI SPEED FANS is located on the top of the cyl head on the 103 engine.There are two plugs there,the one with two wires runs the fans.Disconnecting this plug with the ign "on"should turn fans to HI speed.If this happens ,chances are the sensor in the head is faulty...approx 25.oo for the part,5-10 min to change.Hope this helps.