a/c problem on 850

Discussion in 'Volvo 850' started by sfpd public affairs, Jun 3, 2004.

  1. i have a problem with my a/c. when i switch it on, the clutch engages for
    only a couple of seconds and stop then start up again in a couple of
    seconds. this continues until i switch it off. what seems to be the
    problem. i read from other post that it may be the superheat switch and
    that i can bypass this without a problem.

    should i bypass the switch, if so, where the heck is is. if not, then what
    else should i do or what else is wrong?
     
    sfpd public affairs, Jun 3, 2004
    #1
  2. sfpd public affairs

    John in NH Guest

    should i bypass the switch, if so, where the heck is is. if not, then what
    Sounds like that. The switch itself is the white connector coming from the
    clutch of the compres. to the car's wiring harness. REMOVE THAT CONNECTOR and
    reconnect the wires (with a weathertight connection, of course). Should do it.

    You can see the wires for this job from above when looking down; near the
    radiator on the pass. side.
    ~~~
    Brig. Gen. Mark Kimmitt on the Iraqi "wedding" that was attacked - 'There may
    have been some kind of celebration. Bad people have celebrations, too.'

    My eBay Stuff:
    http://tinyurl.com/u0fi
     
    John in NH, Jun 4, 2004
    #2
  3. sfpd public affairs

    John Horner Guest

    The next step is to test the pressures in the system. An A/C mechanic is
    probably what you need :(.

    John
     
    John Horner, Jun 4, 2004
    #3
  4. sfpd public affairs

    G Klein Guest

    On the 850 it is a expensive repair most shops charge 8 Hours to replace the
    evaporator

    --
    "*-344-*Never Forgotten"
    Is for the New York City Firemen who lost their lives on September 11,2001.
    The official count is 343, but there was also a volunteer who lost his life
    aiding in the initial rescue efforts. And I will never forget them as long
    as I live,
    nor should any American.
    "Mow Green"
     
    G Klein, Jun 4, 2004
    #4
  5. sfpd public affairs

    David Taylor Guest

    I had a quote for mine from a company that had just gained their a/c
    franchise. They quoted me £350 and something like 6 to 8 hours.

    3 days later they still had the car and were still working on it.

    Didn't bother me, I got the quote in writing which is legally binding in
    the UK.

    :)

    David.
     
    David Taylor, Jun 4, 2004
    #5
  6. sfpd public affairs

    Guest Guest

    If the a/c clutch is cycling from cold straight away thenit is NOT the
    overheat switch on the compressor- you are short of gas and the low pressure
    switch is cutting the compressor out. You need a recharge.

    If however the a/c runs normally for several minutes, then cuts out and
    needs 10or so mins before it comes back to life then definately suspect the
    overheat switch.

    Tim..
     
    Guest, Jun 4, 2004
    #6
  7. sfpd public affairs

    barry Guest

    I have the same problem with my T5. I'd like to bypass the switch, can
    anyone direct me to it, and is it easily done?
     
    barry, Jun 4, 2004
    #7
  8. sfpd public affairs

    Mike F Guest

    What do you mean by same problem? If the A/C is cool but not cold,
    compressor is cycling with the period measured in seconds, then the
    problem is most likely low refrigerant. If the A/C works fine for a few
    minutes, then not at all for 10 minutes or so, then the problem could be
    the superheat switch on the compressor.

    The superheat switch is on the back side of the compressor. You need to
    join the 2 wires going into it together. The best way is to follow both
    wire to a connection about 6" (15 cm) away, disconnect the superheat
    switch wires and connect the 2 other wires together. (The connectors
    will just plug into each other.) Do not remove the superheat switch, as
    the refrigerant will come blasting out. Note that the design idea of
    the superheat switch was to save the compressor from overheating, it's
    setting is too low, causing the compressor to turn off when there's
    really no problem.

    Another problem is that the A/C works fine for a while - typically 30
    minutes or more - then cuts out and doesn't work until the car has
    cooled off. This is usually caused by the gap in the compressor clutch
    being too large, and the magnetic force is not enough to engage the
    clutch. (Removing the superheat switch from the circuit as described
    above will help this problem, as it will increase the voltage available
    to the clutch a small amount.) Others have used the wire going to the
    clutch to engage a relay that is fed power directly from the battery.

    --
    Mike F.
    Thornhill (near Toronto), Ont.

    NOTE: new address!!
    Replace tt with t (twice!) and remove parentheses to email me directly.
    (But I check the newsgroup more often than this email address.)
     
    Mike F, Jun 4, 2004
    #8
  9. sfpd public affairs

    Rob Guenther Guest

    Mine did that in my 960 a week or two ago, it was out of R-134, evaporator
    is permeating the refrigerant out, slowly over the course of a year.

    The tech said the 850's A/C system is much more trouble prone then the
    960's, which is bad news for you... Hopefully it isn't too costly (A/C is
    either cheap, or super expensive).
     
    Rob Guenther, Jun 5, 2004
    #9
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