3308676 - L10 CLIMATE CONTROL NOT COOLING

The fan works properly and sends air into the interior compartment in accordance with the set flows, but this air remains at the external temperature and is not cooled.
The enablement to switch on the refrigerating circuit is controlled by the climate control and engine management control units. So if the air conditioning does not cool under particular conditions, this is correct.For greater detail, see DESCRIPTION AND OPERATION 1056 and DESCRIPTION AND OPERATION 5040.
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation
Check the condition of the compressor drive belt Continue to Step 1 Tension incorrect Replace the belt Op.   1092G10 
1CHECKING WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect diagnostic equipment (Examiner or other instruments) to the diagnostic socket. Check that there are no faults in the climate control control unitCheck that there are no faults in the engine management control unit Continue to Step 2 An error is detected in one of the two control unitsContinue following the instructions for the diagnostic equipment
Lack of dialogue with the climate control control unit Restore connection between climate control control unit and diagnostic connector ( See   E6020  AIR CONDITIONING )
Specific software not available Continue to Step 3
2ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Using the diagnostic equipment (Examiner or other instruments) carry out active diagnosis on the operation of the compressor relay Continue to Step 5 Compressor relay faulty Check and, if necessary, replace the compressor engagement relay Op. 5040A04 Continue to Step 5
4 stage pressure switch faulty Replace the 4 stage pressure switch Op.   5040B14  Continue to Step 5
Connections not correct Restore the connection between the climate control control unit and the compressor coupling, via the 4 stage pressure switch and the engine management control unit ( See   E6021  COMPRESSOR ENGAGEMENT ). Continue to Step 5
3COMPRESSOR ENGAGEMENT CHECKAll OKProblems metOperation
Check the correct operation of the compressor relay ( See   E6021  COMPRESSOR ENGAGEMENT ) Continue to Step 4 Compressor relay faulty Continue to Step 3
4CHECK COMPRESSOR OPERATING CIRCUITAll OKProblems metOperation

Check, in order:

 Continue to Step 5 4 stage pressure switch faulty Replace the 4 stage pressure switch Op.   5040B14 
Connections not correctRestore the connection
Faulty componentsReplace faulty components
5CHECK COMPRESSOR ELECTRO-MAGNET COUPLINGAll OKProblems metOperation
Check the operation of the compressor electro-magnet coupling and, in particular, that it is correctly connected to earth Continue to Step 6 Compressor electro-magnet coupling malfunction Replace the compressor Op.   5040A20  complete with electro-magnet coupling
6CHECKING SYSTEM PRESSUREAll OKProblems metOperation
Check the system pressures: See Test   5040B  Check on operation of air conditioning system (pressures) Continue to Step 7 High pressure does not rise or low pressure drops too much: fluid leaks in the circuit Locate these leaks Op.   5040A14  , then repair the circuit
High pressure continues to rise: the compressor cooling fan does not interveneProceed to Step 7NOTE: This fault could be associated with that of 'excessive engine heating' See table   D30 
7HECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that there are no reasons why the climate control control unit or the engine control unit do not enable the engagement of the cooling circuit.For further details see DESCRIPTION AND OPERATION 1056 and DESCRIPTION AND OPERATION 5040End of diagnosisFault persists Search for the fault starting from another symptom'