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Thread: Blower resistor? Fan draining battery...Help!

  1. #1
    Join Date
    Mar 2007
    Location
    Chicago
    Posts
    42

    Default Blower resistor? Fan draining battery...Help!

    I could use a little help with my '01 XC70. Weird...my interior blower continues to run even after the ignition is off. I'm not talking about the "afterblow" 50 minutes later to clear out the condenser, I mean after the ignition is switched off it starts and stops, surging at alternating speeds sometimes until the (new) battery is too run down to start the car.
    After searching this forum and trying everything I could find related to this problem...and being fed up with jump starting the car every day or so, I reluctantly visited the dealer. His conclusion after charging me $100 was that the in car temp sensor was dirty so they cleaned it saying that if this didn't do the trick I might have to have it changed along with the blower resistor. It actually worked the first time I shut the car off at home but now it's acting up again. Has anyone here ever changed this resistor and where is it? Any thoughts or advise would be greatly appreciated.

  2. #2
    Join Date
    Jul 2007
    Location
    Alabama
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    1

    Default

    This has the same thing happen with my friends' volvo xc70 parts...Yes, I would guess that the blower motor resistor is bad. The blower motor resistor is used with the blower motor switch to obtain the different fan speeds. It is easy to change. The resistor is located on the A/C evaporator housing. To remove the resistor, disconnect the wire connector from the resistor and remove two mounting screws.

  3. #3
    Join Date
    Sep 2002
    Location
    Belgium
    Posts
    2,105

    Default

    The fan is driven by the fan control module (shouldn't be a surprise ), item 4/31 in the attached drawing.
    This is essentially a power transistor, I think that in V70 models it is located at the bottom of the fan unit (has a cooling surface and two connectors, a 4 way and a 2 way). If this transistor fails (possibly by not replacing the pollen filter on time, resulting is a constant high current need for the fan to get enough air circulation), it can do so by shorting emitter to collector, resulting in a constant high current and thus running fan. As can be seen from the drawing, the fan control module has a constant power connection so a failing transistor will keep the fan running even when the car has shutdown.
    Although a failing fan module is not the only possible cause of a continously running fan, I think it is worth looking into. In the mean time you may consider to remove fuse 11C/26, as the drawing shows it feeds the fan motor, I think it has no other circuits to feed. Note that the drawing is that of a manual climate control, the fan is controlled in the same way in case of an automatic airco.
    Willy
    Attached Files Attached Files
    144 GL (1974)--->244 GL (1982)--->940 GLE 2.3i (1992)--->XC70 2.5T (2004)

  4. #4
    Join Date
    Mar 2007
    Location
    Chicago
    Posts
    42

    Default

    Thanks for the replies...that schematic will really help.
    I talked to my dealer today to see what he would say about the failed repair attempt. He said the resistor is a $340 part but since I just paid $100 basically in labor the price for the repair would be $260. Anybody know where I can get this besides from the dealer and install it myself? A part # would be GREAT. Unfortunately it doesn't seem to be a part that's sold anywhere online.
    The only reason I can see to go ahead and let the dealer do it is because if it isn't the resistor I'll most likely be able to get my $ back on it. Thanks in advance.

  5. #5
    Join Date
    Mar 2007
    Location
    Chicago
    Posts
    42

    Default Update...

    Called another dealer today to check price/availability of the blower resistor. The parts guys said the part I'm looking for is called the "Power Unit" which is part number 8693262. Said it would cost me $150....Found online for $127. Much better.
    Looks like the first dealer is trying to pull a fast one on me.
    When I googled the part number, Bingo...
    http://www.v70r.com/forums/index.php?showtopic=8992
    It explains the problem. Just thought I'd post this to enrichen the search pool...
    Thanks again Willy and Voltaje...

  6. #6
    Join Date
    Sep 2002
    Location
    Belgium
    Posts
    2,105

    Default

    I ran the part number through the system, it is the module I was talking about in my previous reply,
    see the attachment (item 5). The drawing can give you a good notion as to exactly what you will
    find if you decide to replace it yourself.
    Willy
    Attached Files Attached Files
    144 GL (1974)--->244 GL (1982)--->940 GLE 2.3i (1992)--->XC70 2.5T (2004)

  7. #7
    Join Date
    Mar 2007
    Location
    Chicago
    Posts
    42

    Default Repaired

    I Finally got around to changing the blower resistor/power unit last night. I was indeed the culprit. Everything's working perfectly now and the fan will finally do what i tell it to do and turn off with the knob or the ignition.

    Didn't know what needed to be removed to do this so I used the schematic submitted by Willy (thanks!) and the dash removal and interior air filter photos offered here to figure out how to remove the glovebox and other parts...http://www.volvoxc.com/resources/how-to/index.php

    The glovebox needs to be removed and there are some nasty to get to T25 screws, but all went smoothly. The unit is located under the squirrel cage of the blower assembly so now I'm primed to do the blower motor if/when it conks out. Anybody doing this feel free to PM me for help if needed.

    Willy mentioned that having a dirty pollen filter might cause the failure and that's consistent with what I found. Mine was filthy! I don't even see how air was getting through it. Glad I got that sorted too.

    The only problem I have is that I can't get the little damping arm that slows the glovebox opening to reattach at that ball joint, if anyone has a tip for that...

    Many thanks to the forum and it's contributors...

  8. #8
    Join Date
    Sep 2002
    Location
    Belgium
    Posts
    2,105

    Default

    Hello,
    Good to read you solved your problem (and were pointed in the right direction )
    I have some info regarding the glove box, it isn't much, but perhaps it can help.
    Willy
    Attached Files Attached Files
    Last edited by Willy; 10-24-2007 at 08:55 AM. Reason: Forgot to add attachment
    144 GL (1974)--->244 GL (1982)--->940 GLE 2.3i (1992)--->XC70 2.5T (2004)

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