To check the cooling fan, turn the ignition switch ON, the thermo-switch should be grounded and should be closed to completed the ground when the engine reaches the correct operating temperature. Check the wiring, relays and control unit and replace thermo switch WHERE necessary. After having switched the ignition OFF, unplug the cooling fan wire connector, connect 12 volts to terminal A and join terminal B to the ground; if the cooling fan operates in a squeaky mode, then its replacement is necessary. To make removal and installation the initial step is to remove the negative battery cable, drain the cooling system and remove the upper hose if necessary. Third, further, remove the fan motor wire connector, undo the fan shroud attaching bolts and then remove both the fan and the shroud as a single unit. Disengage the fan and motor from the shroud, place the fan assembly back at the condenser, rejoin all the connections of the wires, and secure any disconnected hoses. Last, when tightening the mounting bolts on 1984-87 models, apply only enough pressure so they are not overly tight and will not break through the plastic material, then on 1988-91 models, apply the force as much as 16 ft. lbs. (22 Nm).