Could be the blower motor circuit breaker opening and closing due to over heating. Also if you are under charged on freon or the cycling switch is old or bad will also make them cycle more among other things. John Hervey -----Original Message----- From: dmcnews@xxxxxxxxxxxxxxx [mailto:dmcnews@xxxxxxxxxxxxxxx]On Behalf Of geoff_ombao Sent: Sunday, July 24, 2005 1:26 PM To: dmcnews@xxxxxxxxxxxxxxx Subject: [DML] Air Condition at Highway Speeds Greetings! Recently picked up an 82 DMC and am quickly finding out about many of its eccentricities ... the most recent one: A clicking sound can be heard from the rear of the car when the air conditioning is on at highway speeds (at perhaps one second intervals). Has anyone else noticed this? 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/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> 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/