Once I got the air conditioning working on the 560SEC it was apparent the auxiliary fan was not working. As can be seen in the wiring diagram below, the W126 SEC auxiliary fan can be triggered either by high coolant temperature or by refrigerant pressure. The diagram is for 1986-1990. In 1990, the W126 went to a dual fan setup. The fan can operate at two speeds based on a resistor.
My fan would not work even when fed 12v directly. I struggled to find a replacement fan from a brand I trust. I wasn’t that keen on a […]