Can A Bad Thermostat Cause The Cooling Fan To Not Kick In In My 91 Honda Civic Sedan

Posted in Cooling Perfomance | Asked on May 30, 2010

I tested the cooling fan away from the car and it works. the problem is that it does not kick in while it’s in the car. Can a bad thermostat cause this?

There are 10 Answers for "Can A Bad Thermostat Cause The Cooling Fan To Not Kick In In My 91 Honda Civic Sedan"

  1. Don M says:

    Yes! It happened to my 96 Infiniti G20, if that helps to know.

  2. Rev. Al Po says:

    Might be a coolant temperature switch. See if you can find a shop manual for that car.

  3. Joe D. says:

    No!
    Faulty relay
    Faulty cooling fan temperatue switch
    Wiring
    ECM (computer)

  4. bumbleb77 says:

    I leaning more towards the coolant temp sensor and/or temp switch that controls the fan relay.

  5. Yvonne M says:

    Is the car over heating if not your fine. If your over heating its a bad sensor or a bad ground or a disconnected wire. Ck power supply to the fan

  6. gdwrnch40 says:

    Joe D has your answer.

  7. robb says:

    joe is correct. the thermostat gives no signal to your fan.. or anything. its just a ground on the thermostat housing.

    ecu, temp sensor, relay..

  8. t0nnY says:

    Thermostat can be causing it. If it is stuck and wont open the coolant isnt hitting the thermal fan switch and no signaling the fan to turn on. I would change the thermalstat first because it is cheaper than messing with your wiring and computer. If you never touched your computer it wont go bad.

    Change thermostat and thermal fan switch.

    Quick fix is to tap you fan signal power wires to switch 12volt. So when you turn your key to second click your fans come on.

  9. Sang K says:

    Yes, only if thermostat is stuck in open position. You would never reach engine operating temperature and fan will not run.

  10. jose o says:

    Your thermostat only controls the flow of cold coolant entering your engine. If your thermostat was faulty and stays open, then your engine will not everheat (no fan needed). If it stayed closed, then your engine will overheat and your fan should kick in.

    Your Engine Coolant Temperature sensor (ECT) near your thermostat sends temperature stats of your engine. If your ECT sensor is bad, your cooling fan may not kick in.

    When above normal engine temperature has been reached, your computer will send a signal to your relay switch to power your fan. If the relay switch is bad, your fan may not turn on.

    Also, if the fuse to your relay switch is bad or the fuse to your fan is bad, your fan will not come on.

    Check your fuses first and work your way back to troubleshoot your fan problem.

    Good luck!

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