Coolant fan RENAULT Megane III Coupe (DZ) (11.2008 - 09.2016)
18.07.25
22.07.25
- @Graziana Venturi22.07.2025 12:34s. H.AUTODOC expertIf the cooling fan on your Renault Megane III Coupe 2008-2016 is constantly on, the service indicator is on, and the diagnostics show "short circuit to ground" but without a specific code, this is a common situation indicating a protection mode.
Most likely causes:
1. Coolant temperature sensor (CTS): The most common cause. If the sensor is faulty (short circuit to ground or gives incorrect readings), the ECU "thinks" that the engine is overheated (or does not see the temperature), and constantly turns on the fan.
2. Wiring to the CTS or fan control module: Damaged or frayed wire that shorts to ground.
3. Fan control module / Fan relay: Internal fault causing constant switching on or short circuit.
What to do:
- Deep computer diagnostics: Use the Renault scanner (CLIP). It can read specific codes and show "live" data from the coolant temperature sensor (check the readings on a cold and warm engine - they should be logical).
- Visual inspection: Inspect the coolant temperature sensor and its wiring/connectors for damage, corrosion, chafing.
- Check the fuses and fan relay.
The problem is very similar to a faulty coolant temperature sensor or its wiring.
Coolant fan constantly on when the engine is running. The car has been on diagnostics there are no fault codes and service light on the dash. The fault that is shown is there is short to earth in the system but it doesn’t say where. Has anyone else had this fault.