2001 Mitsubishi Eclipse A/C Issues

BALSERFAMILY

MEMBER
2001 MITSUBISHI ECLIPSE
3.0L
6 CYL
FWD
AUTOMATIC
134,062 MILES

The car is titled as a 2001 Chrysler Sebring with a 3.0 liter engine. The reason I list it as a Mitsubishi eclipse is that it was made by Mitsubishi for Chrysler in 2001 so it is basically an eclipse. The problem I am having is that the compressor cycles on but will not cycle off, this causes issues because as rpms increase pressure decreases on low side and increases on high side. At 2000 RPMs the low side is at 20 PSI and the high side is climbing above normal operating range way past 350 psi. With this issue the car cools until you drive it and then it starts pumping down. I have changed the cycling switch and this did not do anything to help issue. I am EPA certified for home air conditioning and have a well rounded knowledge of car a/c and how it works but I am at my wits end with this problem. Any help would greatly be appreciated by the way did I mention this is my wife's car and she hates the heat living in Florida does not help.

Wednesday, July 30th, 2014 AT 6:05 PM

5 Replies

JIS001

MECHANIC
3,412 POSTS

When you turn on the A/C check to see that both fans come on right away. If you don't see them come on then you would need to diagnose to see why the fans are not coming on. You may also want to have the system evacuated to see how much Freon is in there and verify that the system is not overfilled. Once the system is drained you would want to pull a vacuum on the system. Do it from one side like the low side and see if it pulls down the high side as well. If it does not pull it down then you have a restriction in the system. You could have a plugged up drier or plugged up condenser. If all is good then your compressor could have an internal problem. If the compressor needs to be replaced then you would also need to replace the drier just in case there is contamination from the compressor. Hope this helps and you have the proper equipment to evacuate the system and do a vacuum test.

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Wednesday, July 30th, 2014 AT 6:57 PM

BALSERFAMILY

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3 POSTS

Your answer did not answer my question. Both fans are running the compressor is only a year old and works correctly. The amount of Freon in the unit is correct for this vehicle the problem is a cycling issue. The compressor comes on fine and works it is not cycling off and on to maintain the pressure at the correct setting and yes I have replaced the cycling switch with a new one. The system has also had a vacuum place on it to replace the cycling switch and it will pull down from the high side or low side. When the system is running as the low side goes down below operating pressure and should cycle off it does not, and in correspondence pressure on the high side goes up I just do not run it until the high side pressure switch can cut it off so as to avoid damage to compressor.

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Thursday, July 31st, 2014 AT 6:48 AM

JIS001

MECHANIC
3,412 POSTS

Well it can come down to either the expansion valve is stuck closed or the one year old compressor could have failed prematurely if the proper amount of oil was not added. And what I meant on the vacuum I would say only pull the vacuum through the low side and see if both low and high side gauges go down. If it does not then you do have a restriction. Hope this answer makes a little more sense. Keep us posted please.

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Thursday, July 31st, 2014 AT 9:15 AM

BALSERFAMILY

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3 POSTS

Yes it pulls both sides down when you place the system on a vacuum through just the low side and yes it pulls both sides down. The proper amount of oil was added to the system it calls for 1.8 ounces of pag oil. The charge was weighed in at exactly fifteen ounces of 134 Freon which is what is specified for the car. I may not be certified for car a/c but I am certified for commercial and residential a/c so I completely understand about levels and checking the system for blockages. I as far as I know the expansion valve does not control the compressor it controls the flow of Freon to get proper cooling. The compressor is controlled electrically by pressure switches for cycling but I cannot seem to find the location of the low side switch weather it is in the compressor or mounted un the dash before the evaporator core. The compressor is working properly because it is compressing it is just not cycling to control pressures better.

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Thursday, July 31st, 2014 AT 12:08 PM

JIS001

MECHANIC
3,412 POSTS

The pressure switch is a dual pressure switch.
Here is instructions to test it. Posting diagrams below.

PRESSURE SWITCH CHECK

1. Remove the dual pressure switch connector and connect the high/low pressure side terminals located on the harness side as shown in the illustration.
2. Install a gauge manifold to the high-pressure side service valve of the refrigerant line.
See image one

3. When The high/low pressure sides of the dual pressure switch are at operation pressure (ON ) and there is continuity between the respective terminals, then the condition is normal. If there is no continuity, replace the switch.
Second diagram is the spec.

Third diagram is location of switch.

Fourth and fifth are the electrical wiring schematic. Looks like there is a separate controller that controls the cycling switch as well.

Image six is the location of the controller.

Let me know if the images are clear or not. If not you can give me a fax number by sending me a private message and will fax you the diagrams. But looks like the automatic compressor control could be the problem if the switch is good.

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