Search for a thread started by me a couple of years ago - auxiliary fan failure analysis. To remove the auxiliary fan frame assembly there are four radially oriented screws at about the 10, 2, 4, and 8 o'clock positions. The radiator does not need to be disturbed, but it's much easier to access the fan frame screws by removing the front bumper assembly first, which is quite easy. There are four nuts on each frame horn, plus 10 mm head screws that hold the bumper surrounds that you access from the wheel wells.

You should also test the mechanical fan clutch. When cold the fan should rotate easily, but at over 100C and you stop the engine it should be much stiffer.

The aux. electric fans are energized by two sensors - one that engages them at full speed when the coolant temp reaches 105C, and a pressure switch in the AC system that energizes them at half speed by dropping the input voltage via the ceramic encased resistor mounted on top of n the LH frame rail.

Duke