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Ross, Diagnostic and repair technician
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Experience:  Licensed diagnostic and repair technician
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I have a 2009 Viano and the air conditioning does not work

Resolved Question:

I have a 2009 Viano and the air conditioning does not work even though the system has been pressured/ vaccum tested, had the purple dye treatment, the engineers have coated the visible pipes with a solution to bubble from the escaping gas.

Any answers or solutions, suggestions please?
Submitted: 3 years ago.
Category: Car
Expert:  Ross replied 3 years ago.

Ross :

Hi my name is***** a car technician and I’ll help with your question.

Ross :

Other than the refrigerant quantity/pressure, there are several other possible causes of the air conditioning not working. Firstly, ensure the air conditioning fuses have been checked, there are several to check.

Main engine bay fuse box:
Fuse 44 (60A) Condenser fan

In the smaller engine bay fuse box:
Fuse 35 (5A) Climate control unit
Fuse 39 (40A) Front A/C blower

The most common cause of the A/C system not to work is either the refrigerant pressure sensor, or the compressor clutch. You should notice when you switch the A/C ON there will be a click from the engine bay, this is the compressor clutch engaging. If this doesn't happen, and the system has the correct gas pressure and quantity, the problem will most likely be electrical.

In theory the fault could be anywhere on the electrical system controlling the A/C, from a faulty switch, control unit, sensor or wiring fault but the pressure sensor is a common cause of this to happen so would certainly be my first part to check, then check the clutch is engaging when power is applied.

If the compressor clutch does engage in when the A/C Is ON and no cold air is produced, the condenser fan will be the most likely suspect, if neither the compressor clutch or fan come on, the problem points back to the pressure sensor.


Thank you very much, I will get those points checked.

Ross :

No problem.


However, what would you say about the fact that the system does not retain the gas. They re-gas the system and then a couple of weeks later the gas has largely gone but they can find no leaks.


They are suggesting the leak is in a hidden place behind the dashboard. Is this a possibility?

Ross :

Ok, if the gas level is dropping and no signs of leaks are found, the evaporator under the dash board certainly would be suspect. These are difficult to get to at the best of times but this does often happen. Either the evaporator matrix its self or the supply pipes where they pass through the bulk head to the evaporator are common areas for leaks to occur.


Thank you Ross,


That is very confirming.

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