1996 olds 88 a/c problem
 

sometimes it works and some times it doesnt. replaced ac control unit in dash from salvage yard and still does same. went over a r/r crossing and it started working, until I turned the fan speed down and all stopped. Short somewhere but where can it be? when working I get power to 3of 4 connectors on the back of the fan control. when not working the only power coming to the whole shooting match is one small wire and I know its not heavy enough to run everything and it goes to a connector on the left side of the panel. when I checked the connector nto the fan switch it was disconnected and I noticed that one had lower voltage than others. It's not the fan switch because nothing there will work when its not working. thanks and hurry, It's hot.

Fyi
 

Found problem. There is a multi wire connector behind the knee panel between the ash tray and steering column. there is a brown wire that apparently feeds the a/c control panel. It had a bad connection in the plug. cut and placed a blade connector. works fine now.