Dodge Diesel Overheating Due to Failed Electric Fan

I had a similar issue with my 2017 Dodge 750 diesel last summer. The symptoms were nearly identical, overheating after short drives and a non-responsive cooling fan. With some experience working on cooling systems, I first checked the obvious, coolant levels and visible leaks. Everything looked fine, but the fan motor stayed silent even when the engine was hot. Took it to my regular workshop where they diagnosed a faulty wiring connection between the temperature sensor and the electric fan motor. The connector had corroded, preventing proper communication. They replaced the wiring harness and cleaned the connection points. Total repair cost was 95€ including parts and labor. The fan clutch and cooling system have worked flawlessly since the fix. No more overheating issues, and I can clearly hear the fan kicking in when needed. Before suggesting specific solutions, could you share: Current mileage on your Dodge, Any warning lights on the dashboard, Whether you notice any coolant loss, If the overheating happens more in city driving or highway speeds This information would help determine if your issue matches what I experienced or if other components need inspection.

Thanks for sharing your experience. My Dodge has 104122 KM and just had its annual service last month. No warning lights showing on the dash, but I have noticed small coolant loss recently. The overheating occurs mostly during city driving, though it still heats up more than normal on highways. After reading about your wiring issue, I checked the fan connections but they appear clean with no visible corrosion. The temperature control system seems to be getting power, but the electric fan still wont engage even when the engine is clearly hot. Perhaps the fan motor itself has failed rather than just the wiring? Would be great to hear if others have needed to replace the entire fan assembly or if there might be other components to check first.

Thanks for those details about your Dodge. After fixing my similar fan issue, I learned quite a bit about the engine cooling system. While my problem was wiring-related, your symptoms do point more toward a potential fan motor failure, especially since the connections look clean. The cooling system relies heavily on proper fan operation during city driving when there is less airflow through the radiator. A quick test you can try: When the engine is warm (not hot), carefully check if the fan spins freely by hand when the engine is off. If it feels stiff or makes grinding noises, the fan motor bearings might be failing. In my research after my repair, I found that complete radiator fan assemblies for these models typically cost between 200-300€, plus 100-150€ labor. Not a cheap fix, but less expensive than risking engine damage from constant overheating. Before replacing the entire unit, have your mechanic check: Fan relay functionality, Temperature sensor readings, Fuse condition, Control module signals These components are much cheaper to replace than the complete fan assembly and could be causing the fan to stay idle despite high engine temperatures. Would you mind sharing if you hear any unusual noises from the fan area when the engine is running? This could help narrow down whether its truly a motor issue or possibly something else in the temperature control system.

Thanks for your insights about diagnostics and costs. You raise good points about checking the entire temperature control system before jumping to replace the fan motor. My Dodge makes a slight buzzing sound from the fan area when running, but the electric fan never actually spins. I will try your suggestion about testing if the fan spins freely by hand when the engine is cool. The grinding noise you mentioned would definitely help confirm if its bearing failure. I called my usual mechanic and scheduled an inspection for next week. Asked them specifically to check the fan relay, temperature sensor, fuses and control module before replacing any major parts. Given the small coolant loss I mentioned earlier, they will also pressure test the cooling system to rule out any leaks contributing to the overheating issues. Really hoping its just a relay or sensor rather than needing the full radiator fan assembly replaced. Will update once I get the diagnosis. The repair costs you shared give me a good baseline for what to expect if the fan motor does need replacement.