AC Compressor not activating. C4 1,6HDI 2011

[akerolf]

AC not funktion. Compressor not activating. If i understand right there are two types of activation. Could it be the pressure switch failing? Is there an easy way to test?
VF7**************[VIN obfuscated, can be read by forum staff]

[RichardW]

Really needs to go on a diag machine to see if it reading the AC pressure OK, or if the pressure is low. If pressure OK, then you can look to see if there are any other indications that it is not requesting AC. If there is an AC request, then you can check that you have the 12V at the connector at the AC compressor.

[xantia_v6]

The compressor operation can also be inhibited by the engine ECU, so that should also be checked.

[akerolf]

Really needs to go on a diag machine to see if it reading the AC pressure OK, or if the pressure is low. If pressure OK, then you can look to see if there are any other indications that it is not requesting AC. If there is an AC request, then you can check that you have the 12V at the connector at the AC compressor.

I have diag but have problem to navigate to right spot. What should I look for?

[RichardW]

Depends on the computer. Looking in the air conditioning ECU for live data (Diagbox calls this Standard Parameter Measurements) to see what the pressure is and whether there is an AC request. You might also look in the BSI live data to check the status of the AC switch.

[ozvtr]

Parametric measures (or live data) in the engine ECU might show the A/C "high side" pressure. Some ECUs report it and some don't. It's the engine ECU that monitors the A/C pressure.
If it does show that parameter, the pressure should be between 5 and 6 BAR and the A/C having not been used for more than an hour.
If it's down around 1 or 2 BAR (or less), the engine ECU wont engage the compressor.