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Clutch to electric fan pressure switch settings?

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    Clutch to electric fan pressure switch settings?

    My 1998 Dodge Durango is getting a large electric fan to replace the mechanical one. It was originally equipped with R134a. I want to add either a trinary or high pressure cut off & fan control switch. My question involves the pressure settings for the fan portion. My shop manual lists the various system pressures:
    Low cut off: Open @ 10 PSI, closed @ 13-27 PSI.
    High cut off: Closes @ 270-330, opens @ 450-490.

    The system also has a low temperature cut out switch called an electronic clutch cycling switch. According to the manual, it opens when refrigerant temp is below 37 degrees, and closes just under 40 degrees.

    In 2001, these trucks came with a pusher fan in front of the condenser. According to online parts listings, they used a common Mopar trinary switch. I can't find any specs on it as far as pressures, and apparently looking at a shop manual it is a transducer that operates on 5V.

    I've shopped switches that have the several functions and just need some advice for fan pressure since there never was any. I can keep the HPCO about where it is for OEM. I've seen trinary and binary HPCO/fan switches with fan ranges anywhere from 164-207 to 238-330 PSI. A bonus would be to find a switch in M10x1.25 since that is what my OEM switch is.

    Thanks for any advice.

    All trinary switches I know of are either straight thread with an O ring or for 1/4 flare with a shreader core depressor

    the above link will get you more kinds of switches than you can shake a stick at. There are a couple of 10mm binary switches, but no 10mm trinary.
    I think you need to add a switch port for either the HPCO or fan depending on what binary switch you choose.
    A transducer sends a varying signal to a controller which make output choices based on the signal it gets, NEVER hook anything 12 volt to a transducer.
    Last edited by Cornbinder89; 05-28-2020, 11:32 PM.


      I've seen a number of 10 x 1.25 trinary switches- here are a couple:
      4seasons 36581, low 30-33, high 325-450, fan 170-220
      4seasons 20963, low 22-25, high unk, fan 195-240

      I have a spreadsheet with some data of several I looked up, I didn't write down the thread pitch on the earlier entries. It's not that difficult to adapt one, so I'm mainly concerned with where my fan should come on.