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[02 MGM LS] A/C takes time to kick in

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    [02 MGM LS] A/C takes time to kick in

    Gentlemen, what am I looking at here?

    The A/C (I got EATC) takes its sweet time to kick in. I think I'd need to check the refrigerant pressure, but it seems to be OK, because when it does kick in, the air blows hella cold.

    The symptoms to clear things up:
    1. EATC works, save for the dead backlighting. It can randomly switch between Celsius and Fahrenheit.
    2. The vent diverter flaps work, reach every direction as commanded (floor, vents, windshield, closed cycle).
    3. When turned on, the A/C will not blow for a long time. Note this: IT DOES NOT blow hot air from the heater core, it blows fresh air when running in any mode other than Max A/C (in the latter case, it will recycle the cabin air).
    4. After a longer time, it starts blowing freezing cold air - as it should when the interior is hot.

    I tested it today in these conditions:
    Outdoor temp 64 F, cabin temp 72 F (the car sat in the sun). Wouldn't blow cold air from the A/C, just the cooler air from the outside (and recycle air in Max A/C). After 3-4 minutes of driving and fiddling with the EATC controls (blower speed, vent selection, Max A/C, turning it off and on again) I left in Max A/C, only then did it start blowing cold A/C air (after 1 more minute or so). When it blows cold air, it's hella cold, so I think the A/C charge is OK. The temp sensors read from the PCM read OK.

    Day two of testing:

    Outside temp 76 F, cabin at just about the same, fired her up first time this day.
    The A/C compressor took 10 minutes (!) to kick in; then it was blowing hella cold air, so I guess there's no coolant leak.
    Left the car for 10 mins on a parking lot, went back, fired it up, the same happened. This time it took the A/C compressor 2-3 minutes to kick in.
    Each time it happened I was switching between Max A/C, Normal A/C, and Auto, to no effect, until the compressor "felt like it".

    Ran the EATC self diagnostic routine, no codes.

    Day three:

    Took a feeler gauge to the clutch plate on the A/C compressor. Read ~0.3-3.5 mm at every 120 deg. point around the circle, and the service manual says the gap setting should be within 0.35-0.75 mm, so I guess it's OK.

    I'm now leaning to an electrical control issue. It's like something is not commanding to energize the A/C compressor clutch magnet to run, as if there was a feedback missing from one of the sensors in the A/C system or the EATC isn't running the compressor until it does.

    Given that my EATC has developed a 'homesick syndrome' (switching from Celsius to Fahrenheit by itself), should I suspect that there's a PCB solder going bad in it and POSSIBLY causing this compressor run delay? As in, the EATC needs to stay tickled with power until it starts responding to what the A/C system sensors tell it and turn on the compressor?

    And if not, what sensor outputs EXACTLY make the EATC resolve that the A/C compressor should run or not? I'll repeat - the A/C kicks in when the compressor is 'told' to kick in, and it is told with a HUGE delay - like, 10 minutes of driving at 80 F outside and 80-85 F in the cabin, when I start the car that sat for hours in the sun (and in this case the EATC blows air into the cabin, just without the A/C until the compressor kicks in).
    '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
    '96 Chrysler Grand Voyager LE 3.3 V6
    "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

    #2
    I know some of the EATC units had an issue with a relay on the board that powers the AC compressor. The solder would crack and it wouldn't feed power out. Apparently they were fixable if you open it up and re-solder the thing.

    http://www.lincolnsonline.com/tech/00261.html

    No idea if that still applies by 2002 but its worth a look.

    The other clue this is the problem is you will not see +12v at the AC low pressure switch on the side of the drier. If you can back probe the connector you can verify if power is coming out of the EATC unit or not.
    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
      You know, it might actually be that.
      Today I kinda forced the sucker to start the compressor by repeatedly cycling between Max A/C, Normal A/C, Auto, and switching over between Fahrenheit and Celsius (by pressing the two outboard buttons on the EATC).

      Say that I would pull the EATC - any specifics on replacing other components aside from the vacuum o-rings?
      '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
      '96 Chrysler Grand Voyager LE 3.3 V6
      "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

      Comment


        #4
        thats usually the only thing that goes. I've had my hands in one of those units before and there isn't exactly much that is user-serviceable inside. The lamps are even soldered in. Beyond the vacuum valves and a couple relays its basically just chips on a board. If the buttons are flaky maybe give them a clean. I don't quite remember if its a rubber membrane that touches a trace on the board or an actual switch button soldered on. If it shows evidence of cap leakage those can probably get replaced but I don't remember there being very many inside.
        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


          #5
          Alright, thanks!

          This might be a good time to resolder new backlighting bulbs into the EATC. All of mine died a long time ago... I got the funky EATC bulb that's half a step between the old wedge-lock bulbs and those soldered ones that sit in round bases of some sort, the bulb bases/holders on mine are rectangular (I already inspected the guts some time ago). I hate taking a soldering iron to any PCB, but a friend I got does this for a living, so this base is covered. That box with assorted sizes of o-rings is gonna be handy too.

          "I would do anything for love—"
          Girflfried chorus: STOP BUYING CAR PARTS!
          "—but I won't do THAT!"

          Will update this thread as things go.
          '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
          '96 Chrysler Grand Voyager LE 3.3 V6
          "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

          Comment


            #6
            Backprobed the A/C low pressure switch, harness side, as follows:
            1. The car was sitting hot in the sun (since the morning).
            2. Started the engine and proceeded to backprobe both wires of the switch on the dryer/accumulator as follows: first the violet one, which feeds power from the EATC relay, then the other one which goes to the A/C high pressure switch (followed by the PCM and the A/C clutch relay).
            3. Both wires read 11.5 VDC, which I assume is OK and the A/C low pressure switch passed power to the A/C high pressure switch.

            SURPRISE, SURPRISE - I took the backprobes from the wiring and resealed the insulation that I'd pierced for this test. A minute later -- not five, or 10 minutes from starting the vehicle - the A/C clutch field coil kicked in nicely, spinning up the compressor.

            Now I wonder should I probe the harnesses downstream of the A/C low pressure switch, and downstream the A/C hi pressure switch, and finally, at the A/C clutch field coil? This tells me something's wrong electrical-wise.
            '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
            '96 Chrysler Grand Voyager LE 3.3 V6
            "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

            Comment


              #7
              Sounds like bad connection. The AC WOT cut-off relay may have issues. It's located in the relay pack on the rectangular vacuum reservoir on the driver inner fender. Sometimes just reseating the relay will help.

              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
                Yeah, I'm planning on testing out the harnesses between the hi/low switches and reseating both relays relevant to compressor cycling.
                The A/C compressor clutch field magnet connector is covered with a ton of gunk tho, it looks like old grease.
                Just to have all bases covered, I'm taking the fat lady to a shop to have the refrigerant charge and leak testing done.
                Last edited by SpitShine_PL; 06-17-2021, 08:10 AM.
                '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
                '96 Chrysler Grand Voyager LE 3.3 V6
                "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

                Comment


                  #9
                  UPDATE:
                  Welp, stumbled upon elves, fairies, unicorns, and all that weird tharmaturgy (or magic) that comes with electrical wiring systems on 19-year old cars.
                  I proceeded with reseating the connectors and relays. Before I got to the harness connector on the compressor field coil, I reseated the A/C cut-out relay within one minute from starting the engine and... BANG, the A/C kicked in instantly, cooling your truly with its best performance. A blessing at 90 F outside!

                  Ah, the mysteries of FoMoCo electrical engineering. The issue seems to be solved for now, tho I will take it to a shop for a refrig charge checkup.
                  '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
                  '96 Chrysler Grand Voyager LE 3.3 V6
                  "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

                  Comment


                    #10
                    Oh boy, this thing is back to pester me again.

                    No compressor run for 5 minutes from a 'cold' start at 92 F oustide. This time I got onto something:

                    Started the car again at a mall parking lot, no heat, despite the sunload sensor in the sun and the ambient temp of 92 F. I popped the hood this instant and what do I see?

                    The A/C compressor pulley STUTTERING to start spinning.

                    Like, half a spin, stop, half a spin, stop, etc. It did so ten odd times, and each stop was shorter, until it spun right up.

                    Am I guessing correctly that there's some sort of interruption in electrical wiring right ahead of the A/C compressor clutch?
                    The belt was running nicely and without slipping, the tensioner wasn't kicking back or anything to suggest a slip.
                    I think the clutch is worn out and might not be pulling in all the way on the first try, or there's something wrong with the voltage between the high pressure switch and the A/C compressor clutch field coil.

                    Time to break out the multimeter and take it to the clutch connector for starters, I guess.
                    '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
                    '96 Chrysler Grand Voyager LE 3.3 V6
                    "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

                    Comment


                      #11
                      If it's an old clutch, could it be so worn that the gap between the clutch plate and pulley gets too big?
                      That might cause slipping since there wouldn't be enough pressure on the pulley.

                      Sadly I can't remember the spec for the gap.
                      1985 Mercury Grand Marquis LS, "Maisa"
                      1995 Chevrolet Caprice Classic STW, "Sally"

                      Comment


                        #12
                        The gap spec is 0.35-0.75 mm. I took a feeler gauge to it and it was at 0.35 (which is actually nice, because the compressor kicks in quietly).

                        I think I found the issue.
                        I took a small steel mallet to the clutch plate/hub and gave it some good banging (tee-hee) all around the circumference. Started the car (it was sitting for several hours in the sun) and the compressor started like champ in less than a minute.
                        I think it's time to take the clutch hub apart, take off the pulley, and regrease the inner splines, the shaft and the shims. I might sponsor this fat lady a new clutch and pulley assembly next month...
                        '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
                        '96 Chrysler Grand Voyager LE 3.3 V6
                        "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

                        Comment


                          #13
                          Nothing moves in there on those splines. The engagement is all by spring. You should not have grease or lubricants in there. If the surface of the clutch doesn't have deep grooves like worn out brake rotors, its fine.
                          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


                            #14
                            Alright, good to know, since I haven't pulled it apart yet.
                            If there's any spring action to kick the clutch plate back when the field coil is deenergized, I don't see it. Is it integrated with the clutch or inside of the compressor input shaft?
                            '00 Mercury Grand Marquis LS, Silver Frost, the "Sharona": runs, drives and currently with mods in progress
                            '96 Chrysler Grand Voyager LE 3.3 V6
                            "You obviously have not been introduced to the ASTM Guidance for Profanity Gauging of Technical Services, Addendum#1, American English to Polish Scale Conversion, by which a repair done at a rate of 35 kurwas per 5 minutes means normal performance."

                            Comment


                              #15
                              Its part of the front plate. It doesn't move very far, just the distance of the air gap, so unless you power it with the engine not spinning you probably won't actually see it.
                              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

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