Announcement

Collapse
No announcement yet.

1988 CV HAVAC Question

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    1988 CV HAVAC Question

    On the above mentioned car, there are two vacuum lines that come out of the HVAC Check Valve. One goes to the vacuum canister ("coffee can"). Does anyone know EXACTLY where the oner one goes? I would think it would go to the firewall for the HVAC system, inside the car. I can see a broken line, from the line in question but no corresponding broken line near the firewall. Any ideas?
    What I Own: 1993 Mercury Grand Marquis GS
    What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

    #2
    You are correct, it goes through the firewall and if I recall correctly, it joins into a big bundle of vacuum lines that go into a big connector just behind/below/to the left of the HVAC control head. It passes through the firewall in a grommet, which when seated in the driver seat, is vaguely in the location your right thigh is pointed at.

    It is possible that it tees off and goes over to do something with the automatic climate control as well, but the basic idea is, that black line is the supply for all of the HVAC controls.

    Current driver: the 91s
    Panthers: 83 GM 2dr | 84 TC | 85 CS
    | 88 TC | 91 GM
    Not Panthers: 85 Ranger | Ranger trailer | 91 Acclaim | 92 Jaaag | 05 Focus
    Gone: 97 CV | 83 TC | 04 Focus | 86 GM
    | Junkyards

    Comment


      #3
      yep, into the firewall and there is a tee. One side goes to the controls on the dash, the other goes to the thermal blower lockout switch, so any leak there will make the whole thing go stupid.
      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


        #4
        Originally posted by gadget73 View Post
        yep, into the firewall and there is a tee. One side goes to the controls on the dash, the other goes to the thermal blower lockout switch, so any leak there will make the whole thing go stupid.
        Two small vacuum lines are seated vertically at the firewall to the right of the tee (looking from the passenger side under the hood). One probably foes to the TBL and one is probably an input to the HVAC controls in the car. Any idea which is which? Looking for the one that goes into the HVAC Check valve.
        What I Own: 1993 Mercury Grand Marquis GS
        What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

        Comment


          #5
          The two coming out the top of the check valve goes to the vacuum (soup) can on the driver inner fender and the other to the HVAC system. The one that goes to the TBL is a line from the HVAC controls IIRC.

          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


            #6
            Originally posted by sly View Post
            The two coming out the top of the check valve goes to the vacuum (soup) can on the driver inner fender and the other to the HVAC system. The one that goes to the TBL is a line from the HVAC controls IIRC.
            Got it! Just strange that I didn't see where the opposite end, away from the check valve, is broken off. I guess it will take a closer inspection as I know a larger vacuum hose was slipped over the factory hose. The broken line has the replacement hose with a partial OEM stuck to it but I did not see a corresponding broken OEM on or near the firewall. If I do see it and it is not broken off right at the firewall, it will be an easy job to repair. I am just curious where the other end is on the car?
            What I Own: 1993 Mercury Grand Marquis GS
            What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

            Comment


              #7
              Both lines should run driver side... ish... of the check valve. One to the passthrough in the firewall (not very far away, but may be under the wiper motor location and not visible from the driver side at some angles) which should be more towards the middle of the firewall, along with the vacuum line to the parking brake release, and the other completely across to the soup can. This line goes under the wiper motor and over the brake booster before making the bend to the soup can.

              Hope that helps.
              Also, the TBL vacuum line is the floor vent actuator line.

              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


                #8
                Found the broken line today after an EXTREMELY frustrating exercise. Every time you try to touch the OEM line, it breaks. It is really a "two handed" job but NO way you are going to get two hands in there. Was able to hold the broken line with a parts picker and slide a slightly oversized vac line over it about 2-3 inches. Same result - mostly air just coming through the defroster vents so still appears to have a vac leak. Not sure if it is coming from the new line being too big (seems tight, however) or broken under the dash somewhere or at the firewall. Would love to know where it comes out, under the dash and then just re plumb a completely new line since the OEM lines suck donkey Kong! I am sure there is a main distribution port, under the dash and then vacuum is distributed to whatever selection is chosen.
                What I Own: 1993 Mercury Grand Marquis GS
                What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

                Comment


                  #9
                  Yeah... I imagine that the original lines are trashed at this point and you're probably best replacing the hard lines. PITA to do that though. BTDT.

                  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


                    #10
                    What is BTDT?
                    What I Own: 1993 Mercury Grand Marquis GS
                    What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

                    Comment


                      #11
                      Been There, Done That

                      I've found the lines in the dash are usually still OK but the ones under the hood, forget it. None of my original plastic lines are still there. it got to the point where there were more patches than original line so I just ripped them out and ran new in rubber hose.
                      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


                        #12
                        Thanks for the explanation - sorry for my denseness. Would be nice to know where the line that is just under the wiper motor goes to under the dash so I could bypass it with all new line. The other end goes to the AC Check valve. There is one line going to the "soup can" and the other goes through the firewall to under the dash but where does it end up under the dash. Now that is the question....
                        What I Own: 1993 Mercury Grand Marquis GS
                        What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

                        Comment


                          #13
                          It goes directly to the HVAC controls. It's the black hose in that multicolor pack of hoses (vacuum source).

                          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


                            #14
                            Originally posted by sly View Post
                            It goes directly to the HVAC controls. It's the black hose in that multicolor pack of hoses (vacuum source).
                            One could probably access it from under the dash without pulling the HVAC Control unit? Then find a way to get the replacement line to the AC Check Valve.
                            What I Own: 1993 Mercury Grand Marquis GS
                            What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

                            Comment


                              #15
                              Yup. access the HVAC controls from the passenger side is a bit easier than from the driver side, but you only need that if you're going all the way. Probably won't need to since you can couple the line where it's inside the firewall from the driver side. You will need to pull the controls to verify that the vacuum lines are still attached to the controls though. There's a couple of speed nuts (those press on metal disks) that hold the vacuum harness to the controls.

                              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

                              Working...
                              X