Aero starters fail on a cycle. The duration to first failure can vary from 10k to 25k miles ish.... but after that they fail on a steady frequency.. though most people don't rack up the mileage for it to be a problem.

The trick is making sure you use a quality part as a replacement and to use a process which makes this job almost a serviceable item.

Always clean the wiring at the same time as this is clearly a contributing factor as you observe.

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