During an air dryer service, the technician finds the purge valve is not exhausting at governor cut-out. What is the MOST likely result?

1. The compressor will fail to unload and overpressurize the system
2. The trailer supply line will lose pressure during braking
3. The spring brakes will apply with the parking control released
4. Moisture and oil are not expelled, so contamination builds in the dryer and reservoirs