Jacksson

I own a W reg (2000) Ford Galaxy (2L petrol) but the air condition is intermittent. When I switch it on you can hear the relay clicking on and off quite fast and sometime it starts to work and other times it doesn't. When It does work it functions and cools correctly. Looking at my Haynes there is a relay 143 which is the A/C clutch solenoid which may be the cause. So where is it situated as it does not appear to be in the fuse box. Further, the clicking sound appears to be coming from just behind the main facia A/C switch. Are there any other relays situated there that might be the cause?