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ATC - a/c switches from recirc to fresh air randomly?

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    ATC - a/c switches from recirc to fresh air randomly?

    resident HVAC experts - having a little trouble with my ATC I think. With the A/C on and about 85 degrees outside, I can hear the recirculation engage and disengage periodically. It will only engage for a few seconds and then disengage for a minute or two. Lever is on full cold and fan speed is on manual High...


    Any ideas? Thanks!
    1984 Mercury Colony Park Wagon - 393 Dart block LS 91mm turbo with 4L80E and 9" 6.24@115 in the 1/8 mile (9's in the 1/4), 4650lbs w driver, AC, Drag n Drive rig 1300hp

    1988 Lincoln Town Car - stock for now

    #2
    It should be on recirc all the time. If the thermal blower lockout under the hood is leaky though it won't be able to pull enough vacuum to stay in recirc mode. I've found that bearing balls make pretty effective plugs, though a golf tee or a screw dipped in silicone also works well.
    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC grandpa spec white and cranberry

    1984 Lincoln Continental TurboDiesel - rolls coal

    Originally posted by phayzer5
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

    Comment


      #3
      Ah yes - are you referring to that plastic fitting/valve in the heater hose? It was leaking and I just removed it...I don't remember any vacuum lines hooked up to it but I will look. Do you know offhand where these vacuum lines would come from? a specific spot through the firewall etc?

      Thanks!
      1984 Mercury Colony Park Wagon - 393 Dart block LS 91mm turbo with 4L80E and 9" 6.24@115 in the 1/8 mile (9's in the 1/4), 4650lbs w driver, AC, Drag n Drive rig 1300hp

      1988 Lincoln Town Car - stock for now

      Comment


        #4
        those two lines go back behind the engine. I'm not exactly sure where and I'm not sure if they're on the newer cars, but there's also a check valve back in there that is also attached to the vacuum reservoir on the driver inner fender that when it goes bad, does funky stuff with the vents.

        Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
        rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)

        Originally posted by gadget73
        ... and it should all work like magic and unicorns and stuff.

        Originally posted by dmccaig
        Overhead, some poor bastards are flying in airplanes.

        Comment


          #5
          What are you hearing? A duct door open and close?
          Pete ::::>>> resident LED addict and CFI defector LED bulb replacements
          'LTD HPP' 85 Vic (my rusty baby) '06 Honda Reflex 250cc 'Baileys' 91 Vic (faded cream puff) ClifFord 'ODB' 88 P72 (SOLD) '77 LTDII (RIP)
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            #6
            Originally posted by drhill View Post
            Ah yes - are you referring to that plastic fitting/valve in the heater hose? It was leaking and I just removed it...I don't remember any vacuum lines hooked up to it but I will look. Do you know offhand where these vacuum lines would come from? a specific spot through the firewall etc?

            Thanks!
            should have been 2 wires and 2 hoses. The wires you jump together, the hoses you plug off. They're the plastic tube type, one black and one blue. They should come out of a grommet almost dead center of the firewall, a bit below the vacuum tree. I forget which is which, but one is tee'd into the source vacuum for the ATC, the other is tee'd into the line to the recirc door. Either one being open would make the system act stupid, though having the source one open makes it massively stupid. It goes to hot defrost whenever you touch the throttle, etc.
            86 Lincoln Town Car (Galactica).
            5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

            91 Lincoln Mark VII LSC grandpa spec white and cranberry

            1984 Lincoln Continental TurboDiesel - rolls coal

            Originally posted by phayzer5
            I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

            Comment


              #7
              I am hearing the door for the recirc open and close...I will check the vacuum lines for the heater hose thing (TBL) as soon as I have the wagon back...I think that must be it since I just took it out...unfortunately I don't remember there being vacuum hoses connected to it
              1984 Mercury Colony Park Wagon - 393 Dart block LS 91mm turbo with 4L80E and 9" 6.24@115 in the 1/8 mile (9's in the 1/4), 4650lbs w driver, AC, Drag n Drive rig 1300hp

              1988 Lincoln Town Car - stock for now

              Comment

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