A/C EVAP Temperature Sensor

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Aug 10, 2020 | 12:44 PM
  #1  
I have a 1997 Camaro SS 5.7L
If the car is parked in idle the A/C is cold as a polar bear butt.
Once starts running the air will stop working and won't cool back down.
If I stop, turn it off and start it again it works again.
My mechanic says it is the EVAP Temp Sensor.
Everything else has been checked and/or change but I am not able to find an EVAP Temp Sensor anywhere.
If anyone has another possible solution or knows who can have it and or what the part number is please let me know.

Thanks!
JJ
St Petersburg, FL
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Aug 10, 2020 | 01:30 PM
  #2  
Re: EVAP Temperature Sensor
The A/C evaporator temp sensor is inside the passenger compartment, with the probe inserted into the evaporator coils. There is a bundle of wires that comes through a large firewall grommet behind the PCM. Once inside, a pair of wires (dark blue, black) with a 2-pin connector breaks off from the rest of the bundle, and connects to the sensor wires. To access the sensor, you have to remove the heater core (accessed from passenger foot well).

There is a diagram showing the location, and detailed instructions on accessing it in the Volume 1/Part 1 of the factory service manual, page 1B1-27.

Free 1996 factory service manual - 97 is the same - courtesy of GaryDoug:

http://www.mediafire.com/?40mfgeoe4ctti

Did the mechanic determine the sensor was the problem using the codes it sets, or real-time scanning?
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Aug 10, 2020 | 06:23 PM
  #3  
Re: EVAP Temperature Sensor
Thanks for the quick response.
I don't know how did he determine the problem.
I would have to ask him.
He knows where it is and said he doesn't want to get into it until we find the part because it is labor intense.
We are having problems finding the part.
We don't even know the part number.
I am good at finding things online but this one has been very hard.
I am going to look at the diagram you sent but if you happen to know the part number or where to find it, that would be of great help.
Thanks again...
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Aug 10, 2020 | 06:41 PM
  #4  
Re: A/C EVAP Temperature Sensor
I didn't post a diagram. It's a link to a free download of the factory service manual.

Sometimes searching here on CamaroZ28.com pays off.

https://www.camaroz28.com/forums/gen...r-dash-688352/
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Aug 10, 2020 | 07:19 PM
  #5  
Re: A/C EVAP Temperature Sensor
WOW!
Not knowing is as much as being blind...
I will definitely take that advice!
Thank you VERY MUCH!!!

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Aug 10, 2020 | 09:16 PM
  #6  
Re: A/C EVAP Temperature Sensor
Make sure the part number is the same between 94 and 96. The linked thread dealt with putting a 94 PCM in a 96 chassis. There's always a chance the part number changed over the years.

In the link I posted above, there is also a file for 1982-2002 exploded parts diagrams. Might shed some light on it.
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Aug 13, 2020 | 11:21 PM
  #7  
Re: A/C EVAP Temperature Sensor
If this really becomes an expensive endeavor: I would cut the wires to the sensor, splice in the new sensor, carefully cut a small hole in the evaporator casing, and stick it inside. Might be good enough.
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Aug 16, 2020 | 04:29 PM
  #8  
Re: A/C EVAP Temperature Sensor
Thank you For the suggestion, but the problem is that the new sensor is nowhere to be found.
It was discontinued.
So I'm going to have to find a junkyard that would still have it or figure out what other GM cars used that part and find them in a Junkyard.
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Aug 16, 2020 | 04:31 PM
  #9  
Re: A/C EVAP Temperature Sensor
I believe it is, but I will recheck.
Thank you!
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Aug 16, 2020 | 04:59 PM
  #10  
Re: A/C EVAP Temperature Sensor
My latest research shows that this part fits any Firebird or Camaro from 1993 to 1997, 3.8 L V6 and 5.7 L V8.
They called it

Pressure Cycling Switch - GM (52458970)

https://www.gogmparts.com/oem-parts/...UtN2wtdjgtZ2Fz
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Aug 17, 2020 | 08:31 AM
  #11  
Re: A/C EVAP Temperature Sensor
Let me see what I can do to characterize the sensor in case you never find a replacement. I have a 94/95 pcm setup and I can measure the voltage at the sensor output and compare with the degrees F reading at each point. Then select a PTC sensor that matches as best as possible. I will get back where with the preliminary results.
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Aug 21, 2020 | 09:50 AM
  #12  
Re: A/C EVAP Temperature Sensor
Thank you!
I appreciate any help.
Down here in FL is pretty much impossible to drive my car without A/C
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Aug 21, 2020 | 09:44 PM
  #13  
Re: A/C EVAP Temperature Sensor
I started to do this and got sidetracked. The two storms heading our way meant I had to hustle to buy a new boat trailer because mine had rusted too badly to use and I need one to get the boat on land before the storms. As I discovered those new and used trailers are in very short supply now due to the business closures and cautions with this virus, but I managed to find one. Give me a few days more, the setup is sitting next to my chair, it's just a matter of time.
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