I changed a cigarette lighter fuse.the overdrive light started flashing and it dont want to shift into overdrive.the air conditioner also stopped blowing cold air.this all happened at once

The replacement of the lighter fuse has nothing to do with the overdrive light flashing. Ensure you replaced the proper fuse. Check the fuse you replaced to see if it has blown, perhaps you replaced the incorrect one. Other than that, start with basic testing of the affected components.