AC pressure transducer - anyone?



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Thread: AC pressure transducer - anyone?

  1. #1
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    AC pressure transducer - anyone?

    First let me thank all of you in advance for your help.

    I need someone with pretty good knowledge or experience to help me with the following AC issue.

    My 01 T&C FWD 3.3L has an AC issue. when I bought it the ac clutch was out. i replaced the clutch, vaccumed the system out and it held vacuum fine , so I guess no leaks. recharged and I believe oil and freon level to be pretty close. new ac clutch clicks in and out just fine.

    the issue is with the performance of the AC. the compressor clutch engages but the 2 under hood elec fans do not come on. the fans are good and will operate with engine temp. I think it is the AC pressure transducer (part # 5019881AB).?? anywhere to buy this other than the stealership??

    I have already replaced the fan relay located on the cross member behind the bumper and - no change to the AC or fan operation. the AC blows cool when you first start it but as the compressor head psi rises the air becomes warm and stays that way. I think this is from the fans not coming on and cooling the condersor core. I tested the operation of the fans on my other van (97) and they come on with seconds of the AC being engaged. unfortanally this van does not use the same transducer for me to swap and test for function. I have no problems with engine temp or over heating. I have no codes or check engine lights. the rest of the van operates just fine. does anyone know how to test the transducer ? or other ideas on this AC issue?

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    No the A/C will never cool properly without the fans running. Since you can not move air across the condenser at idle it will just blow warm air and also run higher head pressure as a result of this.

    I am not sure of the cause of your problem but with a proper scan tool you can actually trigger the cooling fans and check for fan operation that way.

    Will the fans ever run with the A/C off but the engine hot just turing on normally to cool the engine radiator? If not I would suggest looking for a ground wire issue first in the fan circuit if the cooling fans are completely dead.

    One thing also you can do is just verify that the fan motors them selves are not burned up by direct wiring each fan motor with a homemade harness to see that they will at least run. Make sure both fans are isolated in their wiring from anything when you apply 12 volts to them.
    2002 Chrysler T&C bought new end of 2001.
    3.8 L 108,000 avg. fuel eco. 22.4

    2009 Pontiac G8 GT fuel economy not determined yet, currently 22 mpg

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    I've never done it but I've read other threads where folks have jumpered the switch simulating closed contacts in the transducer.
    ******** We took the time to answer your post. Please give us some time and post the fix. You'll help hundreds. ********

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    The fans won't come on until the pressure is above 200 psi or so. You can use a gauge set to test the transducer. The transducer is relatively easy to replace because it sits on a Schraeder valve, that is there is no need to evacuate the system before removal.

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    Thanks for all the ideas. The fans are good and they operate just fine to cool the engine. no over heating issues there. I have come across one page that list the specs for the transducer but not having a full set of ac gauges might make the testing hard.

    Transducer Voltage 0 Volts = transducer faulty or no voltage from PCM
    .150 to .450 volts = Transducer Good/low pressure cut out condition
    .451 to 4.519 volts = normal operating condition
    4.520 to 4.850 volts =Transducer good High pressure cutout condition
    5 volts = Transducer Faulty
    Wire Colors Dark Blue = Switch output to PCM
    Violet/ White tracer = 5volt supply from PCM to transducer
    Black/ Lt Blue tracer = sensor ground


    It might just be time to buy a new transducer and see what happens. ??

    Does anyone have a good suggestion on where to buy this item? I know the dealer wants 113.00 for it and parts.com is 76.00

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    I just came across this information. I am not having any trouble with ac clutch operation but it does go into the transducer operation more. I have to say some of it is too technical for me to do but it did help some.

    http://www.autotechonwheels.com/smjun08.htm

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    Well it looks like 'parts.com" has the best price I can find for the oem transducer. I did perform the key on and off test to see if any codes were stored and found zero codes.

    everything on the van works just fine, except for the AC fans not engaging and the air blowing warm because of this. I will update when the new transducer is installed.

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    Transducer harness testing Intrepid 1995 ES 3.5l


    I don't think my transducer is working I get code 33
    the ac is gone anyway, I cut out the belt.. But my radiator fan speed go high if I click on my front defroster, and ac button…

    I was told to unplug the ac transducer that it would stop send bad signal to PCM if the Transducer was bad.

    I was checking my Transducer harness (with Transducer unplug just the harness ... 3 wires) on my Intrepid 1995 ES 3.5l Yesterday…

    Black with strip light blue = ground
    Purple wire = got 5 volt with the ground
    Dark Blue = got 4.97 volt with ground (Is this normal on the return signal, the transducer is not connected)

    I would imagine that I wouldn't get any volt on the return dark blue wire? Right?

    Is it shorted some were with the purple PCM supply 5 volt?

    Just wondering if it was normal to get a return signal volt output (Dark Blue Wire) to the PCM without the transducer plugged?

  10. #9
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    It may be normal. This depends on the construction on the sensing circuit in the PCM. Also, a 1995 model may have an older type transducer known to cause problems.
    The new type has a different connector, and both the transducer and a new harness plug are sold as a kit.

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