If you pulled the electrical connecter off the blue coolant temp sensor and the high fan did not come on (ignition ON), the fault could be in the sensor, the CCU, the aux fan relay, the fan motor itself or the wiring in that circuit. Bring a jumper from + battery to the 2-wire terminal of the pre-resistor (R15) for high fan (ignition OFF). Jumper to 1-wire side gets low fan. That'll help rule out bad fan motor, and potentially pre-resistor, wiring and relays. But I'm not sure if that will explain why you're blowing #1 fuses.

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1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't