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Discussion Starter #21
Yikes. Alright I'll have to trouble shoot that then. When I read the pressure off the gauges what numbers should I be looking for?
 

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Discussion Starter #23
Hey Eric. It's been a while since I've updated you to what has been going on. I have been quite busy and haven't had the time to even look into the car. Lately the weather has been cool so the A/C hasn't been an issue. But recently I decided to take it to a certified Mercedes benz repaid shop. I have never seen so many Mercedes in one place at the same time except the dealership. Immediately within 10 minutes he diagnosed my problem as the sun sensor. He said the sun sensor is reading the car at a lower temperature than it actually is and in effect shutting the compressor off because it thinks the inside of the car is way too cold. I confirmed this by reading the live data on the climate control system (holding rest for 5 seconds) and the first sensor reading I get is the sun sensor. The farthest right part of my display isn't working but it's just a couple of pieces that's not working but I can clearly see the sensor is reading 30 or so degrees. This makes total sense to me now. I have not enlisted him to fix it yet as he is asking for 275+ CA state tax brining it to 301 so I'm just shopping around to see if there is another shop that can do this. I will let you know after I get the problem fixed what the verdict is. Thank you for all your help Eric
 

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If he has to remove the dash then he is not talking about the sun sensor as the sensor is located on the rear end of the hood near the windshield.

We usually remove the dash to replace the evaporator or its sensor.
 

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Discussion Starter #27
He referred to the in car temp sensor and the sun sensor. Is that the little piece at the front on the dash near the windshield?
 

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He referred to the in car temp sensor and the sun sensor. Is that the little piece at the front on the dash near the windshield?
The in car temp sensor is behind the dash and the sun sensor should be on the hood between the grills.


BIG EDIT, sorry I must fix my head tonight. In car temp sensor is behind the interior lamp at the top center of the windscreen. Sun sensor is on the hood at the rear near the windscreen amidst the two grilles and the evaporator sensor is inside the evaporator which is the big job and needs the dash to come out.

So you need to be sure which sensors he is talking about, the first two are a simply DIY but the evap sensor is a major job.
 

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Discussion Starter #30
Could you show me a picture of the sun sensor? I have no idea which one he was referring too but he pointed out the one on the dash near the windscreen. I've attached two photos of what I think you are talking about.
 

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Correct on both counts, your sun sensor is on the dash instead of the hood for some reason, and the in car temp sensor is behind those little grills in the overhead lamp.

The in car temp sensor comes complete with a small fan which blows air from the cabin over the sensor.

Quite often the fan covers the sensor in dust and small debris which makes the sensor less sensitive, so sometimes just cleaning the mess out helps.
 

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Discussion Starter #34
Is the readings for the temp sensor and outside temperature read in celcius in the climate control system? In doing a reading on the sensors in the car right now and I'm seeing about 30 something but it does not specify if it is celcius or Fahrenheit. This is a US model car btw.
 

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Discussion Starter #35
If it does read it in celcius then my sensors aren't faulty. Because translated into Fahrenheit it comes out to the actual temperature outside and inside.
 

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Discussion Starter #36
I decided to do a test on my sensor (not a legitimate test) but I took an LED strip that I had planned on putting on this far (not sure where yet) and wired it up to the dome light and put the light next to the sensor. This light generates quite a bit of heat so. I held rest for 5 seconds to reveal the sensor valued and the in car temp sensor actually went up all the way to about 40 degrees. Not sure if it's celcius or Fahrenheit.
 

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I decided to do a test on my sensor (not a legitimate test) but I took an LED strip that I had planned on putting on this far (not sure where yet) and wired it up to the dome light and put the light next to the sensor. This light generates quite a bit of heat so. I held rest for 5 seconds to reveal the sensor valued and the in car temp sensor actually went up all the way to about 40 degrees. Not sure if it's celcius or Fahrenheit.
For the American model I would expect it to be in F. But it does show the sensor is working, maybe not 100% but working none the less.
 
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