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  • Heater

    So, one of my New Year's resolutions is to fix all the niggling little issues on my MC and see if I can get them all fixed for less than the cost of a single warranty claim excess. I've already ordered a pair of gas struts to lift the boot lid (£55 for the pair). So far the engine is behaving itself since cleaning the MAF with alcohol (£6 for the can, but I'm not convinced this is actually fixed). Next up is the heating, which blows cold air unless you turn it 9/10ths of the way to max.

    I'm sure others have experienced this one, but nothing comes up in a search. Anyone know what the likely cause is, or even how the heating system works? Looking at the parts on realoem.com I get the impression that there is a cable attached to the heater control. What's on the other end of the cable? If it's just opening/closing a flap to adjust the mix of hot/cold air then I'm guessing that cable just needs adjustment. Any pointers for taking the dash apart to get at it?

    Paul

  • #2
    Paul,

    You previously posted on this very subject only 2 weeks ago:

    Originally posted by pdwarren
    1/2 hour to diagnose the problem at those rates is just criminal. I'll do it now for free, and I know none of the details of how the system works.

    You slow an electric motor by feeding it a lower voltage, and the easiest way to do that is to use a resistor. The control in the car will switch in and out different resistors to give 4 different voltages (the top one will have no resistor).

    Given that the fan works fine on one setting, one of the switch, the resistor, or the wiring between the two is buggered. Given that it's the top one (no resistor) that works, I'd put my money on the resistor. Bear in mind, that when you're on setting 1, the resistor will be soaking up 75% of the energy that the fan uses on full pelt. That's quite a lot, and the resistor will get hot. It's probably cracked.

    2 min on realoem.com reveals that the switch costs $18, and the resistor $24. The part number on the latter is 64111375754 (but double check for your exact model).

    A quick Google found this, which seems to confirm my diagnosis:

    http://www.unitedbimmer.com/forums/t...e-control.html

    Now, all you've got to do is figure out where it is on a Z3:

    http://www.bimmerboard.com/forums/posts/82865

    So, for £20 and 45 minutes you could have it fixed.

    ... and if I'm wrong you'll have invested less than it'd cost you to have the stealer "diagnose" the problem.

    It really pisses me off that someone charging £155/hour isn't competent to give an on-the-spot diagnosis of something that obvious (and, seemingly, common). Do they have any experience at all? Would you trust them to use a screwdriver near your car?

    Paul
    /// Exdos ///
    "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

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    • #3
      No, different problem. manty's problem related to the fan control - the one labeled 0-4. My problems with the heat control (the one that goes from blue to red). The problem I've got is that you get stone cold air until the heat control is horizontal and pointing to the right (i.e. well into the red).

      realoem.com confirms that the fan control has a rotary switch behind it, but doesn't make it clear what's behind the heat control.

      Paul

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      • #4
        Paul,

        In that case, I would suggest that you check your coolant level; you may have a bit of air trapped in your water hose to your heater. Try bleeding the cooling system at the highest point to see if air comes out. I've had this problem before with a previous BMW 5 series.

        Hope this helps
        /// Exdos ///
        "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

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