Air-conditioning compressor
I have a 2006 Vauxhall Corsa 1.2 with 82,000 miles. My problem is that the clutch compressor does not engage when the air-conditioning is switched on. The refrigerant registered zero. There is a video on youtube that shows you how to hotwire the relay, but I’m a bit worried about getting it wrong and sending 12V to the ECU and overloading it.
Can you tell me which relay turns the compressor clutch on and off? I have put 12V straight to the compressor terminal, but there’s no operation and the engine is not running. I have filled the system with refrigerant and the gauge now reads full, but this is with the compressor off. I assume that once the compressor kicks in l will need to add more.
Also, have you any idea how to test the magnetic clutch? Geoffrey Rawlings The first warning I will make is that the air-conditioning compressor should not be run with the system empty. One of the reasons that the air-conditioning system should be serviced professionally is that the complexities of the system require more than just a top-up. The amount of refrigerant in the system needs to be carefully monitored – too little or too much will affect its efficiency.
It is also a legal requirement to check the system for leaks once it’s recharged. The refrigerant capacity for your Corsa is 650 grammes and the lubricant for the compressor is Synthetic PAG fluid and the filling capacity is 150 CM3.
As you have connected the compressor’s magnetic clutch directly to a power source without it operating, it is likely that the windings of the magnetic clutch are faulty. I would first check this using a continuity meter. By using a test light or voltmeter, it should also be possible to check the feed to the clutch unit. One of the criteria for the operation of the clutch is sufficient pressure in the air-conditioning system; the sensor for this can be found on the receiver-dryer. The relay that controls the clutch should be K62 – this is regulated by the ECU and fed by fuse 31 in the passenger compartment fusebox.