help please - lost power to cigar lighter , dome light , map light and more 1972 dart

ok , here's what happened so far . everything was back to working fine in the Dart . then i again tried the air pump . lights out in seconds , after putting the last 20amp fuse in . then i took the Valiant to get more fuses . thinking along the way , ..... maybe that drivers side door jamb switch that has been acting up could be the problem . so , when i got back , put a new 20 amp fuse in with both doors closed . plugged the air pump but did not turn it on . opened the passengers side door , no dome light . wiggled that sides door jamb switch , dome light came on , then went out and burned out fuse in seconds . so then took the pump plugged it into the Valiants cigar lighter and buzzt' , burned up the fuse/lights out . so , i am 92 percent sure its just the air pump shorting out . since both of these cars were fine for years . i will update if this is not the case . thanks to everyone .