Radiator fan not working – Hyundai Sonata 3.3 L 2006

Car Forum Repair & Maintenance Radiator fan not working – Hyundai Sonata 3.3 L 2006

  • Adon
    Community Member
    August 29, 2022 at 12:06 pm

    Hello all, I have a 2006 Hyundai Sonata V6 (145k). It is overheating and cooling fan is not turning ON. Car dashboard does not show overheating (fumes from hood observed). Thermostat is good – opens when hot. Here are the details and status. Please advise a solution. Thank you.

    1. AC works, fan turn on slowly when AC is on. Fan does not turn on without AC.
    2. Fan relay is good (tested after removal). If I jump pin 87 and 30, the fan turns on, without car key.
    3. MAIN relay is good (tested after removal). 12 V on pins 87 and 85. If I jump pins 87 with pin 30, the fan turns ON (good speed) without car key. This confirms that fan fuse (50A) and MAIN relay fuse (30A) and SENR3 fuse (10A) are good.
    4. With this, I expected the fan to turn on when PINs 1 and 3 on the Coolant Temp Sensor are jumped. Unfortunately, the fan is not turning on even with car key in ON position. I think PCM is not providing ground to MAIN relay. Not sure why. Cannot think of another fuse or relay to test. I am thinking of replacing the temperature sensor. But I am not convinced that Temp sensor is the issue as jumping that sensor harness (pins 1 and 3) did not turn on the fan. Pin 1 gives 5 V and Middle pin gives 9 V which looks correct based on internet research

    This issue started after I replaced the rear upstream oxygen sensor and cylinder head gaskets. There are two grounding wire on top of front cylinder head. The car does not start with these wires disconnected. And fan used to turn on with car key in ON position. When I touched the wires to ground (cylinder head), the fan used to stop. Car stopped doing this now.

    Has the PCM gone bad somehow? Is there a fuse between PCM and MAIN relay ground (pin 85)? is there anything to test in the fan control module? I tested all relays and fuses in the engine compartment fuse box.

    Brand: Hyundai
    Model: Sonata
    Year: 2006
    Engine: 3.3 L