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Compressor wont cycle off and on.

I wonder if the transducer causes this issue..or maybe it is the ATC??

The compressor will not "Cycle" meaning that the compressor stays on all the time, so do the radiator fans. That is, if you turn the AC on.

The system cools fine. , so I cycle it off and on manually for now at the ATC unit. Though I have seen the frost on the lines, I bet this thing was on the verge of freezing up at one point.

I also get error code 23, Keep in mind also, I replaced the evaporator last year, with some success. I believe the problem occured after that, but I really cannot pinpoint that, unless I disassemble the dash to see if any wires aren't connected. Thought I double checked that.

Essentially, the system cools very well. Air duct temps as low as 38 degrees!

This is a 93- 3.3 intrepid.

What do you think?

Thanks

-Dave
 

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When you changed your evap did you pull a vac on the system?
Your evap sensor switch is inside the evap if it is bad your comp. will run constantly. to do a byte check turn temp to 75 degrees press and hold all buttons on the top row of the ATC except the A/C button untill the display starts to flash it will cycle through all functions checking everything then it willl display your faults . 35 is your evap switch cost about 26.00. Mine was doing the same thing yours is then it just quit working. Hope this helps
 

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Yep..Actually, had a mechanic pull the vac, and do the recharge. I did the ATC code fault process. I just get a code 23, which I believe is the temp blend door feedback, or some such function.

When you say it is in the evap, you mean the housing where it sits? I recall there being a probe, and that is about it.

I thought the ATC itself may have something to do with the issue, and maybe this code 23 is in part, due to an occasional occurance, where the temp is warm even though the compressor is on, and temp is set at 65 degrees. I turn the temp to 90, back down to 60, then up to 90, then to a desired setting. Then the system cools. It is like the ATC falls out of calibration. Running the code check often clears the temperature problem too.

Thanks for posting

-Dave
 

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My ATC was doing similar problem. I got another rebuilt ATC off of EBAY warranty for a year. It was about 41.00 and you send your old one back to him. He said mine had a crack in the powersupply. He does all the common failure mods so you get a good one. If your Low pressure line is freezing like mine was from the compressor all the way inside the evap. then the air flow would almost go to nothing coming out of the vents. I would turn off the compressor then frost would start blowing out of the vents as the evap would thaw the air flow would increase and you would go through the whole process again.
From what one of the guys here on the forum told me once the the probe gets to freezing or what ever the setting for the sensor switch is it cuts the compressor off. But I never got code 35 which is evap switch until it just quit working. When I pulled out he probe it was broken at the shaft. It basically looks like a meat or refrigeration thermometer. It should be stuck in the evap fins like a roast.
 

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You da man!..I believe the problem may be the probe itself. I do not believe it is poked in the fins of the evaporator..It may just be sitting in the housing. I would have to look at the diagram to see what entails getting to it without dissassembly of the plenium box.. gosh I don't want to go through that again!..

I'll take it one step at a time, and thanks for the link for the ATC guy. At least i'll get my ducks in a row..In the meantime, I can still get good AC comfort, with manual cycling.

FYI..I got the frost too, blowing out at me like spit balls. Kinda cool.. and refreshing. I'd rather have that, than the alternative.

-Dave
 

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Remove passenger side heater duct
Looking up with light and mirror or with your head on the floor looking up you will see a round plug with 2 wires on it
There is a lock tab on the plug that keeps it in place. Lift up on tab and rotate plug 1/4 of a turn and the plug will come out
You can insert the probe into the fins from this acess hole
If there is not a hole already in the evap stick the probe in slowly and gently bend the fins to get it to go in the first layer
After it goes through it needs to go into the second layer move it around and gently push it will go into the second layer
You can even use a little RTV or silicone to keep it in place
Start up car and see if compressor cycles
Reinstall plug and heater duct
This want take you long at all if the probe is going bad the compressor want cycle or even want come on. the probe itself at the dealer is only 26.00 chump change as compared to the pressure switch and schrader valve 85.00 and ATC 41.00 rebuilt but my air works perfect now :fun_84:
 

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Great..Thanks Dude...I prayed that getting back to the probe would not be a big deal. Let me tell you, getting that plenium box out to replace the evap was a bear. But all in all, that was an enjoyable project. I learned a lot, and saved a few bucks. I took my time, and rented a car during the project. The entire dash has to be pulled back, and ideally taken out of the car. I hung my dash from the sun visor supports.

As memory tells me, I can say with some assurance, that the probe is not affixed to the evaporator. When I reassembled the box, I placed the probe back into it's moorings, and just "Assumed" it was getting a temp sense from the air.
 

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Hey WB..Good call, the probe was the culprit. Actually as I suspected, it was not mounted into the fins of the evap. I did as you said, or at least as best as I could, now getting routine cycling of the compressor. Job well done my friend.

Only a little problem, in that I did have a devil of a time getting the unit out, At first when I turned it 1/4 turn, the whole "Disc", fell into the housing, and had to fish it out. I see it has a key way on the top and bottom, but I can't seem to get that disc to lock back in. Any tricks? It was today that I determined that I have turned to be far sighted. I can't see up close as well these days. So for now, that disc with the connector is just hanging free..

Thanks again,,, it worked like a champ
 

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Same issue

Intrepidude said:
Are you sure it's the actual compressor coming on and not just the fan? I was doing the same thing (engine running while I slightly moved the transducer wiring harness off and on and the fan would kick on and off but not the compressor. This also lead me to belive there was a wiring problem. I still don't know what was causing my clutch to not activate, probably a glitch in the computer which sends a signal to the relay for controlling the clutch based on temperature sensors and engine conditions (WOT, etc).

How did you fix this problem. This is the same thing that I am having troble with on my 1998 Intrepid.
 

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transducer

The transducer is sending a signal to the Powertrain control module. While it is possible for it to fail, generally the compressor will not start if the refrigerant is low to begin with. The transducer is sending this signal depending on the pressure in the system. It is also linked to the throttle position sensor, and is part of the process that increases idle when the compressor kicks on.

If you are having a problem with fans, there is a device called the "modulator" mounted down low on the fan housing, that directs the signals for high-low fan modes. this fails and often leaves you with one fan running.. making overheating a possibility.

If the probe in the evaporator fails, (Or falls out in my case) the compressor will not stop running. at least with regard to evaporator temperature. Jumping the connections will tell you if the probe connections are defective...the compressor would have come on (Provided the ac is in fact, ON). If the compressor does not come on, then suspect a low charge in the system.
 

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The cans of 134a are pressurized. If you hook up a can of 134a onto it and open the valve, it will go in, however, intrepids will run the compressors even with very low pressure (which is why so many compressors cease up) so i would track your problem to some other thing.

Also, did you check the pressure already? If there's pressure in there, chances are pretty good it's your transducer, but to make sure it's not your compressor, short the relay and see if the compressor starts up (instructions are farther up on this thread).
 

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If compressor want come on it's either ac transducer evap sensor switch or clutch itself. Perform atc test 35 is evap sensor. See If you get 12 volts to compressor. If the evap sensor is bad the clutch will not engage which is no 12 volt at compressor. From what I read on these forums alot of evap sensors are bad but everyone changes ac transducer first 80.00 evap sensor only 26.00 which can give you numerous problems from the compressor not coming on and system freezing. Good Luck
 

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I just tried 2 recharge my a/c I got pressure but it's not gettin cold I have a 96 3.5 ES

Was there any positive pressure in the system before you recharged it?
 

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One ounce of refrigerant will give the same pressure statically (not running) as many pounds. The reason that I was asking is to tell if you had no pressure then air (moisture) could have gotten into the system and this will cause poor performance. Do you have actual manifold gauges that allow the low and high side pressures to be seen?
 

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Do u have to buy those gauges because I don't see any on the A/C is it possible to drian the system and start over with new R-134a if so where do iI start
 

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These are external gauges used by professionals. It is illegal to purposely vent R134a into the atmosphere. What a private individual does in his/her own driveway is their own business. The system will have to be evacuated (vacuumed) to remove any moisture in the system, then it can be charged. Without the proper gauges it is a "crap shoot". Low side pressure should be approximately 35 psig and the high side pressure should be 2.4 times the temperature in degrees F.
 
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