The Haynes manual is correct. When the ignition is turned to on (only), the fuel pump will normally run for a second or two and then turn off until the key is turned to Start and the engine is running. When turned on, the fuel pump should not turn on and off.
Is it just the fuel pump that turns on and off with the ignition in the on position (engine not running)? Does anything else turn on and off as well?
Not sure if this applies to the 99 Impreza, but on later Legacy based platforms, there are a pair of “test mode connectors”. These are usually not related. When they are connected and the ignition is set to On, the CEL will flash, the radiator fans will cycle on and off, the various solenoids will cycle on and off, and, I believe, the fuel pump will cycle on and off continuously. As the name suggests, test mode connectors provide a means of checking the operation of these components, but the connectors should not be attached during normal use of the machine.
Prior to the fuel pump symptoms, was there any work done on the car that might have caused someone to connect the test mode connectors and not disconnect them?
