As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON DEPARTURE FROM A SCENE LOCATION, THE HYD LIGHT ILLUMINATED WHILE EN ROUTE TO THE HOSPITAL. DIVERTED TO & HAD A GND AMBULANCE MEET THE ACFT AT THE AIRPORT TO COMPLETE THE PATIENT TRANSPORT. FOUND THAT THE HYD PRESS SWITCH HAD FAILED. THIS SWITCH WAS REPLACED WITH A SERVICEABLE SWITCH. THE ACFT WAS THEN RETURNED TO SERVICE.