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  1. #1
    Join Date
    Oct 2009
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    Tavistock, Devon
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    Rad thermostat question.

    Hi everybody,

    I have a problem with the red fan not coming on and overheating.

    I do have a manual override switch that works.

    I have replaced the radiator thermostat but I still have the problem of the fans not coming on automatically.

    Has anyone got one of these? If so how is it wired. I have 2 wires from the stat, one to earth and I have a single feed wire from the stat that goes to the relay via a connector plug.

    I have tested the relay and it works fine. There are 4 pins on the stat,



    Anyway, any help with what the problem could be would be gratefully appreciated, thanks.
    Attached Images Attached Images
    Cheers,
    Murray


    That's the trouble with you Sailors, long hair, quick zips and, Oohh, look at the size of that!!

    If I agreed with you, we'd both be wrong.

  2. #2
    Join Date
    Sep 2009
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    Leeds
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    i've only managed to find this Murray:

    https://www.ebay.co.uk/p/FAE-37960-T...Fan/1320835273 - pictures give some info which may help - but didn't mean much to me - lol

    not sure if it means top to pins are for 95-90 range and bottom 2 are for 100-95 range or what.

    further investigation indicate it's a 2 stage thermostat switch, stage 1: 95-90, stage 2: 100-95, Ford part.

    Gary
    Last edited by nealgs; 30-03-18 at 09:19 PM.
    Conny - A Carnival Red Metallic (paint code Ref: Jag CGG/1811) Southern Roadcraft V8 ( SRV8 ) with 383ci stroker chevy.

  3. #3
    Join Date
    Aug 2009
    Location
    Birmingham
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    534
    Hot water and a continuity test, that would be the best way.

  4. #4
    Join Date
    Oct 2009
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    Tavistock, Devon
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    Gary, yes that's the one I got, the wiring bit didn't help me either.
    I think I am going to do a test as suggested by Daryn but using a hot air gun and try to see what pins do what.
    It should work as it's brand new!

    Thanks
    Cheers,
    Murray


    That's the trouble with you Sailors, long hair, quick zips and, Oohh, look at the size of that!!

    If I agreed with you, we'd both be wrong.

  5. #5
    Join Date
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    1,980
    You’d be better using water and a thermometer to test what temp the switch is working at.

    Where is it positioned in the cooling circuit?

  6. #6
    Join Date
    Oct 2009
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    Craig,
    It's the thermostat that screws into the radiator.
    Have to get the camping stove flashed up!!
    Thanks all.
    Cheers,
    Murray


    That's the trouble with you Sailors, long hair, quick zips and, Oohh, look at the size of that!!

    If I agreed with you, we'd both be wrong.

  7. #7
    Join Date
    Feb 2003
    Location
    Honiton, Devon
    Age
    52
    Posts
    7,736
    Hey Murray, if it's not the relay and the stat proves to be fine is there a fuse somewhere in the circuit that is not involved for your remote switch?
    Perhaps ringing out the cables will show you something?
    2003 Dave Brookes Dax 350ci Chevy SB.
    2008 Crendon 462ci Ford Sideoiler FE Chassis No.43
    2012 Crendon 351ci Ford Cleveland Chassis No.24
    2014 Crendon 452ci Ford FE Chassis No.66 (in progress)

  8. #8
    Join Date
    Sep 2015
    Location
    Berkshire
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    16
    I don't know he background so this may be a daft comment. Has it been working already or is this a new build??

    If the thermostat is switching at 100 (switch fan on) and 95 (switch fan off) where in the radiator is the stat positioned.

    A good radiator / fan should give you a 10 to 15 degree temperature drop through the radiator, top to bottom. So if the stat is at the bottom, the coolant could need to be at 115 degrees at the top before the stat switches on. Depending on the pressure cap you are using you may never reach 115 degrees before the coolant boils.

    If the stat is at the top of the rad, then switching at 100 shouldn't be a problem.

    Just a thought.............

    Nigel

  9. #9
    Join Date
    Oct 2009
    Location
    Tavistock, Devon
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    SORTED!
    With a bit of time to spare to think and play yesterday, I got the old rad stat out and wired it up different ways whilst using my multimeter
    and a hot air gun to see what happened. Well I got a circuit when wired up differently to what it was whilst in the car.
    Got both high and low temp switch on and off.

    So for some reason I must have managed to pull a wire off at some time and put it on wrong when I noticed. I cannot remember that.
    Unless it has always been like that from when I got it last year? Who knows, anyway it is working now so very happy.

    Thanks to all who helped with comments and advice, I wasted a lot of time in tracing wires and head under dash sorting and testing relays
    but at least I have more knowledge of the wiring system now!

    If you look at the top picture in my previous post then the high temp is the two top tabs and of course the low temp switch on is the lower two. (Neal wins the prize)

    Thanks again, one Happy Chappy here now!
    Last edited by Murray; 04-04-18 at 02:04 PM. Reason: Give Neal credit
    Cheers,
    Murray


    That's the trouble with you Sailors, long hair, quick zips and, Oohh, look at the size of that!!

    If I agreed with you, we'd both be wrong.

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