My 1991 MBZ 420 SEL broke down on Highway 5 South and was towed in to PR's Autohaus. Ben and Jose promptly diagnosed the problem as a bad alternator and replaced it. They had the knowledge to know that the amperage the re manufactured alternator that was installed was putting out was not enough. They continued to trouble shoot the problem and found an issue with the wiring and fixed that.They road tested the car and let it run with the lights on and checked to make sure that it was charging properly before they sent me home to Santa Cruz, Ca. The car has never run better, They are a 5 star shop and were life savers! Mark L Waldor