UrbanGardener

I would further inspect the wiring at the gasoline pumps. Ensure there are no interruptions.

I have connected pins 30 and 87 on the relay, and the high-speed fan activates. Arrow in the image. I am also lacking a fuse or relay in the center, as shown in your photograph. I highlighted my picture. Uncertain about its purpose.

I appreciate your response. Upon bridging the S32 pressure connections, the low-speed fan activates. Does this indicate that the auxiliary fan resistor is functioning properly? Intending to purchase copper fuses.

Thank you very much. The maximum temperature I have seen so far is midway between 100 and 120, which I believe is either 105°C or 110°C.

Question: Why does the auxiliary fan not activate when I detach the coolant temperature sensor connection? I can hear the relay clicking when I bypass the coolant temperature sensor connection. Observation: A FUSE is absent from the little fuse box next to the main fuse box. Should I insert a blue fuse there, or should it remain empty? Attached is the picture along with the circles. Thank you in advance.

I have thoroughly researched the auxiliary fan problem on this topic, nevertheless I have been unable to discover the solution. I seek assistance from someone. This pertains to the auxiliary fan of my 1991 560SEC. My vehicle in Southern California does not overheat. The maximum temperature I saw ranged from 100 to 120°C, particularly when ascending a hill. In my previous W124 E320, the auxiliary fan would activate at high speed if I unplugged the blue coolant temperature pin with the ignition on or the engine running. I inserted a 1.1 ohm resistor, resulting in the fan activating at a reduced temperature. However, I attempted to do the same change on my current 560sec, however the fan does not activate when I removed the Blue Coolant Temperature sensor connection. The low-speed fan does not activate upon starting the air conditioning, which I assume is due to a low freon level (the AC compressor engages, and I see bubbles through the condenser glass, however the AC does not emit cold air) or a malfunctioning auxiliary fan resistor. I was unable to access the resistor since it is situated behind the brake booster. Do you have any recommendations for accessing or inspecting the resistor? When I bypass the high-pressure temperature switch of the AC condenser, the fan activates at maximum speed. Upon doing investigation, I successfully identified the auxiliary fan relay C (the blue relay in my vehicle, as seen in the attached picture), and when I connect pins 30 and 86, the fan activates at high speed (with the ignition off). The fan activates regardless of whether the coolant temperature sensor is attached or unplugged. Measured the coolant temperature resistance, which is around 1.3 ohms at elevated engine temperature; likely not indicative of a faulty coolant temperature sensor.