A San Francisco cable car maintenance man who was awarded an expense-paid Hawaiian vacation as last month’s Municipal Railway Maintenance Worker of the Month is in danger of losing his job. Louis Valdivies, 35, didn’t score high enough on civil service tests for permanent status as a cable car switch repairman. He has been a temporary Muni employee for six years. “I know the whole job with my eyes closed,” he said. ". . . It was just the test.” The city transit system is looking for another temporary job for Valdivies.