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94 940 cooling fan thermostat 900 1994

My 740 had a sensor(thermostat) on the upper pass side of radiator for turning
on the cooling fan. I can't locate it on the 940, and I think it is bad. Can
someone please tell me where it is located on this car? Thanks.








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    94 940 cooling fan thermostat 900 1994

    It turns out that the 3 switches in front of the condensor are the problem.
    The gray one turns the fan on low as soon as there is pressure in the line.
    This one is bad. The brown one turns fan on high if it gets above a preset
    preassure (don't know the value). No one I have talked to knows what the purple one is for, but no one replaces it. Volvo tells me these switches go bad
    often. I just ordered the brown, the gray, and the ecu sensor. Will let everyone know if this fixs my problem. Do I have to replace the r134 or are
    these like the low pressure switch? Thanks








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      94 940 cooling fan thermostat 900 1994

      Dear bhouston,

      Good p.m. and may this find you well. On p. 40 [Volvo Service Manual, Climate Control, Section 8 (87), 700/900 1982- ], it states:

      "Pressure switches (3,4,5)
      3=Safety switch (purple) (high-pressure cut-out)
      4=High pressure switch (grey) (FC, high speed)
      5=High pressure switch (brown) (FC, low speed)

      ...

      The safety switch stops the compressor if the pressure becomes too high (over 28bar/406psi for R12 and over 30 bar/435psi for R134a

      The following models are equipped with a further two pressure switches (4 and 5) to operate the FC in the high and low-speed modes:
      940: Four-cylinder engine, 1992-
      960: Four-cylinder engine, 1992-
      960: Six-cylinder engine, 1992-
      960: Six-cylinder engine, 1994-

      In the 1995 960 960 with a six-cylinder engine, pressure switches 3,4 and 5 are replaced by a linear sensor."

      Hope this helps.

      Yours faithfully,

      spook








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    94 940 cooling fan thermostat 900 1994

    Mine is the lh. The problem is it doesn't come on soon enough, and goes off
    too soon. I can watch the level of coolent in the expansion tank go way up
    then the fan comes on and it goes back down. This doesn't seem right to me.
    I have had several times when it boils over, but the gauge never goes above
    the center. Any suggestions?








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      94 940 cooling fan thermostat 900 1994

      If your car has the LH system, the the computer turns on the fan (the AC will also turn it on but that's a separate issue). The computer gets its temperature info from the temperature sensor under the intake manifold back by No. 4 cylindar intake. I'd do the following:
      1. Replace the engine thermostat if it is a few years old. (maybe do this first)
      2. Clean out the radiator fins with a water stream.
      3. Drain and flush the radiator and engine, add new coolant.(see no. 4 below)
      4. While the coolant is drained, check the resistance of the temperature sensor. Remove the sensor, cool and heat the sensor and measure its resistance at the following temperatures:
      @14F (-10C) 8260 - 10,560 ohms
      @68F (20C) 2280 - 2720 ohms
      @176F (80C) 290 - 364 ohms.

      By the way, have you checked for trouble codes?








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    94 940 cooling fan thermostat 900 1994

    You have three sensors that control the fan, they are in front of the condensor on the passenger side. One kicks it on when the AC comes on; one kicks it on if the temperature rises above a certain degree, and I'm not really sure what the other one is for, as I've never had to replace that one.








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      94 940 cooling fan thermostat 900 1994

      Some 940's like my Turbo have a two speed cooling fan and the last sensor may be hi limit temp for it?








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    94 940 cooling fan thermostat 900 1994

    As Brain S said, the LH cars, at least on my ’94-’95s, that sensor doesn’t exist. I believe the ECT (engine coolant temperature sensor) located on the block, controls the fan operation (I don’t know what else would) along with the fuel mixture via the control module.

    Check the fan relay behind either headlight, wiring and terminals, or the fan itself.
    --
    Tom F Back to three 940s. Mods, RainX. Lien holder on two more (the kid's). Rust in pieces, '78 245








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    94 940 cooling fan thermostat 900 1994

    940 with Bosch LH 2.4 fuel injection does not have a thermostat for the fan; rather, the fan is controlled by pressure switches in the AC system, and by ECU. A 940 with Rex Regina FI should have a t-stat in the radiator, I believe...

    - Brian '93 945T








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      94 940 cooling fan thermostat 900 1994

      My '93 940 with Regina has the switch in the upper left corner of the radiator. It was a PITA to put in the new radiator, very tight.







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