We have a service truck that we do repairs to. We use this truck for road calls and to go pick up parts. My business repairs trucks and trailers, How would I record a repair to my service truck in my books?
about if you're a sole proprietor and this is your primary
vehicle? This wouldn't be considered a Auto Expense then would it?"
There are two many Variables for how the tax regulations for Vehicles apply, in the US, to the different entity types. In general, a Mixed Use (personal and business miles) vehicle means you don't report Actuals as business expense.
Your "primary" vehicle is not one of the Tax Rule tests, in other words.