Radiator always running high
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Radiator always running high
I have a c350e 2018 model, 5 seconds after i turn on the engine, the radiator fan runs high and doenst go down, but it goes off when i turn off the engine. I also cant use the e-mode.
need help
need help
Newbie
Joined: Nov 2025
Posts: 18
Likes: 0
2018 C300 (w205, m274, 725) and 1995 Ford Bronco (5.8 Windsor)
Radiator fan Concern
Im a former benz tech. This is usually a problem with power, ground, or signal going to the radiator fan. To avoid overheating issues, the radiator fans integrated control until defaults to 100% duty cycle. The best way to tackle this issue is disconnecting the battery, finding the pin (i forget which pin) for the signal wire that goes between the ECU and radiator fan. Test resistance, it shouldnt read any higher than 0.3 Ohms, but as long as theres continuity, you should be ok. From there, I'd check the ground to the negative jump post mounted to the body. Should be continuity there as well. If both of those aren't the problem, then I'd check the power wire from the fan to I think its the fuse box. Obviously, I'd check the fuse first (dont remember the fuse specifically but its in the fusebox in the engine bay) and then move onto that power wire. Seems backwards from a standard approach, but its worked well for me. Since the radiator fan is part of engine management and specifically a coolant operation, the hybrid function stays disabled as the computer doesn't know the status of the radiator fan. These hybrids have coolant running through the motors, batteries, and since its a 250e, the coolant pump runs off of the hybrid battery as well. If all else fails, replace the radiator fan. Hope this helps
