Joe, Fan speed 3 & 4 power come directly from the battery / alternator and go thru the CB the 3 and 4 relay to the blower motor. If the mode switch doesn't turn on the relays then 3 & 4 relay's won't be turned on. Speed 1, 2, 3, get there power thru the mode switch and go thru the resistor then blower motor. The mode switch power comes thru #18 fuse. John Hervey -----Original Message----- From: Joe OBrien Subject: [DML] Air Conditioner vacuum controls, tech help please. Well, I've been working on the AC system on 16851 for a few weeks now to get it ready for summer. Most everything seemed ok on the car, but there was always one kinda weird scenario in the controls via the mode switch. 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/