Any wiring between the power feed i.e. fuse box and the pump
it could be so many diffrent things google "error codes for a 1994 fleetwood brougham" it will send you to myweb.accesuss.com or .net..very usefull in tracking down the cause
Possibe blown fuse
Check the A/C fuse, that's what happened on my '85.
Stress
Abrasion
a fuse, relay, bad ground or positive wire at switch or solenoid, etc.
tomato ketchup can cause hyperactivity depending on how much you eat
politics and resources.
Gas
Chemicals from factories will cause air pollution. Also, cleaning and styling products are pollutants as well. Fires burning items besides natural vegetation also cause pollutants.
this happened to me alot and i am not a car guy, but it seems the mechanics have to adjust the vacuum pump
poppy seeds