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Old 04-17-2008, 09:20 AM   #1
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Default A/C Issues

Outside temperature is 70 degrees F.

When I start the car the ECC temperature flashes for a couple of minutes. I turn on the A/C with the temperature set to the lowest and I the A/C clutch engages and stays engaged. One of the metal lines from the dryer which I assume is the unit on the passenger side closest to to the firewall is very cold. The temperature coming from the vent is around 60 degrees but I don't get cold air. The A/C clutch never dissengages.


Any suggestions?
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Old 04-17-2008, 10:58 AM   #2
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Is the blower working properly? If so, you should get air at different flow rates (but maybe not the correct temperature) depending on the setting. If the air is blowing normally, but is too warm and the AC seems to be working, the air-mix actuator would be the likely suspect.
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Old 04-17-2008, 12:08 PM   #3
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Which line is very cold, the lower line to the accumulator on the firewall (the canister looking thing) or the upper line from the accumulator?
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Old 04-17-2008, 12:58 PM   #4
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Quote:
Originally Posted by bill buttermore
Is the blower working properly? If so, you should get air at different flow rates (but maybe not the correct temperature) depending on the setting. If the air is blowing normally, but is too warm and the AC seems to be working, the air-mix actuator would be the likely suspect .
Yes blower is working at all speed levels. Yes I get air at different rates. I checked inside the left side peep hole inside that glove box with the cover removed and a lever moves back and forth when I raise and lower the temp. on the ECC. Anything else I should check?
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Originally Posted by Echo SSEI
Which line is very cold, the lower line to the accumulator on the firewall (the canister looking thing) or the upper line from the accumulator?.
The lower, smaller metal line on the canister looking thing is much colder to the touch then the larger higher linet.
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Old 04-17-2008, 01:42 PM   #5
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The larger higer inlet sould be very cold and, at least as cold (or colder than) the lower line. Believe me, I am no expert on A/C stuff under the hood, but it sounds as if the system could use a shot of R-134a to bring it up to spec. Do you have a gauge to check A/C prsessure?
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Old 04-17-2008, 01:52 PM   #6
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The larger line is not cold at all to the touch Bob. I do have several cans of R-134a freon, wait, if I remember correctly I may have one of those disposable that I can take a picture and post. Give me time to resolve another issue and I'll post.

Do you think the blinking ECC could be related to low freon, even during the cold weather and not using the A/C part of the system?
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Old 04-17-2008, 01:54 PM   #7
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Quote:
Originally Posted by Maymybonnieliveforevr
Yes blower is working at all speed levels. Yes I get air at different rates. I checked inside the left side peep hole inside that glove box with the cover removed and a lever moves back and forth when I raise and lower the temp. on the ECC.
If the plastic arm on the air mix actuator is still connected to the flap and moves back and forth with changes in temperature requested, your actuator is functioning properly. If you can get a significant change in temperature from the vents by going from max heat to max cold, that would imply the actuator and linkage are connected and working.

My understanding of AC systems is limited, so I will leave it to others to provide you with additional help at this point.
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Old 04-17-2008, 02:31 PM   #8
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That top line should get ice cold, Frank. Recently, I had no A/C, only whatever the temp was outside, and my larger line was not cold at all to the touch, but the bottom smaller line was. My compressor clutch was engaging as it should (like yours). I bought a can of freon with the built in gauge and found my low side pressure (the larger upper line) read at the port was about 27psig on an 80*F day. I found the chart below and added refridgerant until the low side read 34 psig and I have had ice cold air ever since. So, apparently, the pressure was high enough to engage the clutch, but apparently not enough for the compressor to function and compress the refridgerent properly to cool the air. I may have a legitimate leak, or some may have just leaked out over the years as seals shrunk (especially during non-use in winter), but I am now on the second month of having cool air.

Here is the pressure/output temp chart from the '97 FSM.

Temp----------Humidity---------Low Side (in psig)-------High Side (in psig)--------A/C Discharge Temp
60*F-70*F----Low (<40)-------23-31 psig-------------------140-190 psig--------------39*-49*
60*F-70*F----High--------------25-33 psig-------------------155-200 psig--------------42*-50*

80*F-----------Low (<40)-------27-35 psig-------------------165-220 psig--------------45*-54*
80*F-----------High--------------29-37 psig-------------------185-245 psig--------------47*-57*

90*F-----------Low (<40)-------34-42 psig-------------------185-260 psig--------------50*-60*
90*F-----------High--------------37-45 psig-------------------190-280 psig--------------53*-63*

100*F----------Low (<40)-------38-48 psig-------------------200-300 psig--------------55*-65*
100*F----------High--------------39-49 psig-------------------210-310 psig--------------55*-65*

110*F----------Low (<40)-------42-55 psig-------------------230-340 psig--------------60*-70*
110*F----------High--------------42-55 psig-------------------230-350 psig--------------60*-70*

A/C pressure switch set points to disengauge the A/C clutch are 430 psi and 44 psi.
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Old 04-17-2008, 06:56 PM   #9
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Ok, that chart is a bit techincal for me so I'm going to have to read it again.


Bill, Bob, I did another test and these are the results. I had the A/C on max and at the highest temperature setting on the ECC the center vent read 148 degrees F. at the lowest setting the temp read 57 degrees F. The outside temperature during the test was 75 degrees.

This is the only gauge I have at my disposal, should I look for a replacement or with this due the job for now?

What should be my next approach?




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Old 04-17-2008, 07:08 PM   #10
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The next step is to screw the cap with the trigger onto a new can of R-134a. Start the car and set the AC to max cold. Remove the cap from the suction fitting on your car AC line; pull the trigger on your charging setup for a few seconds to purge air from the charging line, then connect the blue charging hose to the suction port and observe the pressure. You may want to find a heavy rubber band for that trigger so you don't grow old holding it in. You will want to keep the can upright so it charges as a gas. Upside down will put liquid into the suction line. If liquid makes it to the compressor, kiss it goodbye. Use the chart Bob provided. You will be reading low-side pressures. Charge some refrigerant, then undo the trigger and let the system run. Give the system a few minutes to equilibrate before recording the pressure. Check the temperature at the vents and don't charge more than you need for cold air. Placing the refrigerant can in a pan of hot water will increase the pressure and help it move into the system. Securing the can and charging hose and driving the car will help to get the refrigerant into the system even more quickly.
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