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  • HELP – Toyota Radiator Fan on all the time
  • younggeoff
    Full Member

    Hi got a 97 starlet and the radiator fan comes on as soon as the ignition is turned on. I think it’s the radiator fan switch that’s the problem, anything else I may need to check.

    Cheers

    mastiles_fanylion
    Free Member

    Thermostat

    Del
    Full Member

    your diagnosis sounds good. could be the relay but switch is exposed to a lot of stress.
    look for the switch on the radiator – it’ll likely have two wires going into it. pull the connector off, switch on the ignition, if the fan doesn’t start up you are likely correct.

    Del
    Full Member

    ‘stat controls flow of water into the radiator, and allows the engine to warm up to operating temperature, before diverting water to the radiator to prevent overheating as required. nowt to do with the fan 🙂

    mastiles_fanylion
    Free Member

    Not the mechanical stat on the radiator, the ‘stat on the fan – if it assumes the engine is overheating (because it it faulty) then I don’t see why it wouldn’t be that…

    (Although I am not a mechanic – it just seems to stand to reason to me)

    younggeoff
    Full Member

    Del, I unplugged the connector on the switch (located on the stat housing) and hey resto the fan doesn’t run. I’m going to put a test meter across it tonight, my understanding is that it should be an open circuit until the collant temp gets up to 84-90 degress C and which point the circuit is made and the fan will run. I’ve checked the fuse box and there’s two relays marked FAN, they’re both the same so I swapped them round and it made no difference. I’ll check them tonight to make sure they’re ok. I want oto be sure befoer I buy a new swictch as they’re £35 at the local motor factors and £65 at the dealers 🙁

    coffeeking
    Free Member

    Usually on toyotas that fan control (when done from a thermostatic switch) is a failsafe – the fan stays on if the sensor is disconnected. Get yourself a wiring diagram, all will become clear.

    younggeoff
    Full Member

    Oh so when I check the thermostatic switch it should have continuity until the coolant gets warm. So I’ve got the wiring or the relays to check to see where the fault is 🙁 Trying to get a wiring diagram for a 97 Starlet is difficult as there’s no haynes manual for it.

    Del
    Full Member

    well, the fan works, the relays appear to work, if the wiring was at fault i wouldn’t expect a different result from pulling the connector off the switch?
    is it a two pin connector?
    if so, what happens if you short the two pins in the wiring. i’d expect the fan to come on. if it does, get a new switch.
    maybe i’m out of date, and rad switches are thermistors or something these days, but i’d expect they’re still bi-metallics on a ’97…
    of course these days i just call the AA 🙂

    caledonia
    Free Member

    I got a copy of the full wiring loom diagrams for my Golfs and for my new Avensis from the download site which is in the news a lot these days !
    And a new version of the Toyota Sat Nav disk (£250 saved !)

    5lab
    Full Member

    call your local breakers i would expect to pay no more than a tenner for a rad switch

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