Presented into the workshop in the last 24 hours we had a 2012 VW Passat with a complaint of an inefficient Air con system and only warm air out of the blower inside the cabin.
Firstly I ran the system and monitored pressure and checked for DTC’s in the HVAC system where I was presented the common fault of low refrigerant pressure, no surprise there.
Next I evacuated the system and weighed the Gas and only found 54 grams, where we would normally expect a nominal 550 grams in this particular setup.
A quick nitrogen pressure test proved very quickly that the condenser had a mahoosive hole in it which was subject to previous front end impact damage and required replacement.
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We managed to get one same day and quickly installed the new condenser, carried out a second pressure test @ 10 bar for 15 mins, recovery and regas with the correct 550 grams of refrigerant.
It was at this point I ran the system cleared dtc’s and monitored the pressure, it was to my amazement the pressure very quickly rose up to 32 bar where eventually the compressor would stop running until pressure dropped below 24 bar and then straight back up to 32 bar ! In fear of blowing the shiny new compressor into a million pieces it was then I decided it probably wasn’t a good idea to repeat the test.
I also noted whilst looking at live data that the refrigerant temperature rose up to 55 degrees ! I also noted that the main condenser fan hadn’t kicked into life which was ultimately causing this alarming and sudden rise in refrigerant pressure !!
I presented the car for further inspection on our ramp and removed the engine belly pan cover to expose the condenser fan and wiring socket.
As you can clearly see the main earth wire had become dislodged from the main socket which was preventing the fa from operating.
So quick top tip, if you ever see the AC refrigerant pressure going completely nuts just make sure the Fan is capable of working correctly and especially check for damage to the socket located at the bottom of the condenser as this is the second time we have come across this exact problem !![/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]