'68 Coronet with AC

Heating, Cooling & AC

  1. JimKueneman

    JimKueneman Well-Known Member

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    The AC controls. Is it normal for the blower fan and the connector at the back of the vacuum switch (makes the contact for the AC compressor clutch) to get so hot that you can burn your fingers on the pins? I had to rebuild my vacuum switch (the plastic pins were brittle and the back snapped off, drilled and tapped #4 screws to fix it. I also have pulled these two switches apart and cleaned them up and made sure they worked nice a free. I have no other conclusion other than this is normal but man they get hot.... It has discolored the phenolic board where the spade connectors are connected to the board.

    Also should the AC compressor be engaged when the heat button is pressed? I can see why it may be to dry out the air for condensation on the glass but just checked to see if that is they way it should work.

    Jim
     
  2. JimKueneman

    JimKueneman Well-Known Member

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    Figured it out. I will post a link later to my build thread on how to rebuild the AC vacuum switch and blower motor switch and fix corrosion in the rivited lug terminals on these switches. This is a MUST do on ANY restoration and is so much easier when you have the damn dash out......
     
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    • Billccm

      Billccm Well-Known Member

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      In my TV repair days we scrapped the revit heads with an xacto, applied some rosin paste, and gently heated and solder flowed.

      Off topic slightly; the AIS motors for 2.2 mopars would be intermittent out of the box new from the dealer. Pull back the rubber boot and solder flow of the revit heads fixed them 100% of the time. I'm in the habit now of doing this whenever I replace a component with revit connections.
       
      Last edited: Jul 2, 2017
    • JimKueneman

      JimKueneman Well-Known Member

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      Yup precisely. Though one of the phenolic boards is brittle and fell apart as it was burned black. Working on some reconstructive surgery before committing to a new blower switch. The Ultra Rare AC vacuum switch is all fixed and ready to install.
       
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      • Billccm

        Billccm Well-Known Member

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        Fiberglass resin can sometimes reinforce a phenolic PCB. DeOxIt can get all of the carbon tracks out. I've sometimes soaked phenolic in alcohol, dried overnight, and pasted with JB Weld. It is a one time fix when you resort to JB Weld.

        Can you take Vector Board and remake the PCB?
         
      • JimKueneman

        JimKueneman Well-Known Member

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        I JB Welded it together. It is possible to make a PCB board. I have it now so that it is at the measurement limit of my fluke measured at the connector (I am SO SO SO SO glad I replaced all the harnesses that were available, several of the pinch on connectors had failed with high impedance at the switch too. I had to solder the wire to the connect as well as the connector to the rivet). Even with this low DC impedance the switch gets hot at the rivets, it must be the low impedance finish is worn off the nubs and under load the impedance goes up. I before I was measuring about 300mV across the vacuum mounted switch (now it is 60mV and cool) and about 600mV across the main switch (now that it is repaired it is about 200mV so it still get warm. It is way better but I am going to look for a NOS switch.
         
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        • Billccm

          Billccm Well-Known Member

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          I've had good luck using these to make little PCBs both in radios and even pinball machines. They are pricey, but you can shear off a little and make boards for any application. I'm sure you have these laying around in bench drawers at work, too.


          https://www.vectorelect.com/circbord.html
           
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