Aneesh

My understanding of the pressure switch goes as follows. Please correct me if I am wrong. Contacts 1 and 2 should form the compressor clutch activation circuit while 3 and 4 should form the fan high speed switch. So, under normal conditions, contacts 1 and 3 should be supplied with 12 V DC. Under normal operations, the pressure switch contacts 1 and 2 should be normally closed and contacts 3 and 4 should be normally open. Test Results Now only the pin wire 3 has 12 V supply. Hence 1 is not receiving 12 V supply. seems like maybe some sensor somewhere is cutting of supply to pin 1. So i think it should not be a relay problem. Could you suggest what sensors are connected in series before the supply reaches pin 1. Also, when pin 3 and 4 are connected, the fan does not start spinning in high speed. I guess this is another problem, but more related to safety than functionality.

Hi, I am Aneesh from Portugal. I own a Citroen Xantia 1.9 TD (1994). Recently my AC compressor stopped working. I took the connectors off the pressure switch above the dryer. It had 4 contacts. With a wire I joined the middle 2 contacts and the compressor clutch worked and the compressor started working. I refilled the gas into the system but still have the same problem. I thought maybe the pressure switch is defective, and replaced it with one from a friend's car, but it still doesnt work. Can you please help me debug it. Also I cant find the wiring diagram anywhere online, and I have no idea which contacts out of the four in the pressure switch are normally closed. Is it the middle 2? Do you think it could be a relay problem, since all the fuses are fine. Please let me know ur suggestion at aneesh84@gmail.com