I purchased my 2004 CTS in Jan,2016 and the owner told me that the air conditioner needed charged. test show system full. i'm reading there might be a relay. there are 7 relays in the fuse box under the hood none indicates clutch. which one is it. I like to replace before going further. thanks

 

hello suppose to be 90 degrees today. please advise relay.
thanks
stickman161

 

In the under hood fuse block near center lug is a micro relay 1/2 the size of a normal relay. CMP CLU is how it's labelled. Fuse is one relay away from it. Owners manual will have location and fuse descriptions. The underhood fuse block cover should also has description and locations

 

the COMP CLTCH is a 10 amp fuse that tested ok. I see no relay.
there is a relay missing in the fuse box, "DRL RELAY .MICRO-OPT
THANKS

 

what is the missing relay do?

 

post a picture of under hood fuse box if you can. DRL RELAY is for daytime running lights