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Thread: astra g heater matrix / coolant shut off valve

  
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    gregg123's Avatar
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    astra g heater matrix / coolant shut off valve

    Hi all I'm back again with the same problem - no hot air, tried everything and no joy so now its time to change the heater matrix, but I have a few questions.
    Firstly iv heard the problem could start from the air recirculation button below the heater controlls, well mine has stopped working (just the recirculation button).
    When I refit the new heater matrix can I get away with not connecting the plug for the coolant shut off valve, or would that just cause it to close again and ill still end up with the same problem.
    Iv also tried connecting a 12 volt feed to the 2 wires at the back of the air recirculation button, but had no joy, so any help now would be great
    Cheers gregg

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    Any1???...

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    Spedo's Avatar
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    When you say you are back again and you have tried everything you can't assume your previous thread has already been read, therefore it might help if you list what you have already tried in order to to fix your problem, that way people won't waste their time going over what has been tried but instead come up with a new soloution.

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    no hot air

    hi
    ive got the same prob as you with my astra heater, did you get it sorted if so what as the problem?
    i have fixed mine now but am intersted in how you fixed yours, if you did fix it of course.
    text me if you prefer
    regards steve 07973 303965

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    is your thermostat ok???????
    women are like cars....cars are like women.....both trouble and money!!

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    just a follow up for everyone

    the engine thermostat has nothing to do with your heater blowing cold air!

    if your heater feed pipes under the bonnet going through the bulk head behind the engine to the right are hot then your problem is almost always the heater shut off valve which is very well hidden behind the heater unit inside the car.

    this is out of view and has two wires going to it which powers a small motor with 12volts to close the valve and reversed polarity 12volts to open the heater water flow valve.

    these two wires are part of the smaller wiring loom/plug on the back of the dash heater control panel, from what i can remember as you look down behind this panel it is the second and third wire on the smaller plug BUT PLEASE CHECK FOR YOUR SELF BEFORE PUTTING 12VOLTS DOWN IT AND DON'T FORGET TO UNPLUG IT FROM THE HEATER CONTROL UNIT!

    all you need to do is feed it with 12 volts and reverse the polarity, you should hear the motor turning, when it stops your valve should be in the open flow position and you now should have hot air READ ON!!

    NOW THEN if you have read this and you have a more in depth knowledge of how this air con heater setup works then i would love to know at what point does the heater control unit on the dash close this water flow valve??

    if anyone has this problem with their Astra g mk4 then please contact me and i will help if i can

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    Just thought i'd post a little follow up from my own experiances with this problem.

    I had a very similar problem to this with my car and thought that I was going to have to shell out for a new matrix and remove the dash etc etc.. Came across this post and Steve's postings and contacted him about it. Really nice chat Steve and thanks for your help on this btw. It turns out that there's some differences on the small plug with the placements of the wires which is why it didn't work with me.

    Anyone else having issues with their heating, especially with a car with A/C, then Steve's quick stop solution above is perfect but with one addition. The wires you are looking for are coloured Black with a blue strip and Black with a yellow strip. They aren't always in the same place.

    Close all your doors, windows and kill anything that could make a sound and feed them 12 Volts. If you hear a click then swap the polarity. You should hear a little whirr and a click. That's the valve opening. Once you have that, reconnect the power to the control unit and turn over the engine and put the heat up full and fan on 2 or 3 and wait for the engine to heat up. If you start to get blistering heat after 5 mins you've found the problem!

    It seems that there's an error in the Heater Control Unit with the little microswitch that controls the valve motor. If the above solution fixes the problem, you've just saved yourself anywhere from £100 to £500! all it takes to fix it totally is a new HCU which you can get from most scrap yards for a fiver or a new unit online for £28-£35. All that and you don't have to totally strip the dash!!!

    If you can't be bothered to totally fix the problem this solution will work completely, just be aware that the matrix will ALWAYS then be hot instead of being able to be bypassed when you have the A/C on.

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    Imdelcross's Avatar
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    I have tried this remedy with my astra 1.7 dti 2001 model and cant hear the valve opening i reckon tne valve has packed in completely How can i remove it to check it out. Does the dash have to be stripped out. Please help as this is driving me crazy

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    I have fixed this heater hot air issue twice on these astras.the heater dial behind it cables are attached to it,the casing of the cable is held by plastic clips,when the clip breaks the casing becomes free and therefore selecting becomes in effective.

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    Quote Originally Posted by f927 View Post
    I have fixed this heater hot air issue twice on these astras.the heater dial behind it cables are attached to it,the casing of the cable is held by plastic clips,when the clip breaks the casing becomes free and therefore selecting becomes in effective.
    do u mean the cable is detatched at the valve or at the circular control knob below tne radio

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