* Faulty Radiator Fan Relay: This is the most common cause. The relay acts as a switch, controlled by the PCM (Powertrain Control Module), to turn the fan on and off. A faulty relay can stick closed, causing the fan to run even when the ignition is off.
* Faulty Cooling Fan Temperature Sensor: This sensor monitors coolant temperature. If it's malfunctioning, it might be sending incorrect signals to the PCM, leading to the fan turning on inappropriately.
* PCM (Powertrain Control Module) Issue: While less likely, a problem with the PCM itself could be sending the incorrect signals to the relay, causing the fan to cycle on and off erratically. This is a more serious and expensive potential problem.
* Short Circuit in the Wiring: A short circuit in the wiring harness leading to the fan or relay could cause power to reach the fan even when it shouldn't. This can be difficult to diagnose.
* Faulty Fan Control Module (if equipped): Some vehicles have a separate fan control module; if your Caravan has one, it could be the source of the issue.
Why removing the fuse stops it: The fuse is a safety device that breaks the circuit when there's excessive current. By removing it, you're completely cutting off power to the fan motor, thus stopping it. However, this leaves your vehicle vulnerable to overheating if the fan *should* be running.
Troubleshooting Steps (in order of increasing complexity):
1. Check the Relay: Locate the radiator fan relay (consult your owner's manual or a reliable online repair guide). Try swapping it with another relay of the same amperage rating (if you have one that's not critical, such as the horn relay). If the problem moves to the other circuit, the relay is faulty.
2. Check the Cooling Fan Temperature Sensor: This is usually located in the engine block or radiator. You might need a multimeter to test its resistance values (compare to the specifications in a repair manual).
3. Inspect Wiring: Carefully inspect the wiring harness leading to the relay and the fan motor for any damage, chafing, or exposed wires. Look for signs of shorts or melting.
4. Professional Diagnosis: If you can't identify the problem after these steps, it's time to take your Caravan to a qualified mechanic or auto electrician. They have the tools and expertise to properly diagnose the issue, potentially using a scan tool to read diagnostic trouble codes (DTCs) from the PCM.
Don't drive the vehicle with the fuse removed for extended periods, as it could overheat and cause significant engine damage. Get the underlying problem fixed promptly.
