That's the fan relay following the compressor cycling. It's supposed to do that, the speed of the cycling on/off is dependent upon pressure on the low side of the freon system. The pressure is dependent upon: Freon Charge Outside temperature Fan speed Engine RPM 4 seconds is probably too fast unless it is cold out and the fan speed is low. Is the system generating cold air from the vents? Is it an R12 or R134 system now? dave s --- In dmcnews@xxxxxxxxxxxxxxx, "daviddelorean" <daviddelorean@...> wrote: > > When I turn on the A/C I have a constant clicking noise. It is coming from directly behind the drivers seat almost as if it's directly behind my left ear. It almost sounds like a relay clicking. It clicks at 4 second intervals. It occurs whenever the A/C knob is turned on. The fan speed doesn't affect it. Any ideas? My A/C is new...installed 6 months ago. > ------------------------------------ To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnewsYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/