Hello and thank you for your question.
If you own an S-Corporation, is the car titled to the corporation or is the title in your name? If the title is in your name, you may have unreimbursed expenses (it goes on your Form 1040 not the 1120S) or perhaps you are being reimbursed by the corporation under an accountable plan (deduction to the corporation and a reimbursement to you, but again the vehicle would not go on the 1120S).
If the title is in the S-Corp name, it can appear as part of the machinery and equipment total on page 4, schedule L, line 10.
You may also be claiming depreciation on the vehicle if it was purchased in the corporation's name. In addition to page 1 of 1120S above, line 14, See Form 4562:
I trust this answers your question. Thank you again!
If you prepare your taxes, then you'll have to perhaps manually make sure you are entering information correctly, but otherwise your accountant will want to know that you purchased a car in the business name, the date you purchased, the amount you paid, who's driving and for what reasons, etc. If the asset account (balance sheet accounts / lines) has increased, it will generally get picked up properly for Schedule L. The depreciation and cost of the car, again, should show up on the above forms too.
For bookkeeping purposes, debiting the balance sheet account would be proper upon purchasing the car (again, put to the balance sheet line). To depreciate the vehicle as applicable, you would make a debit to depreciation expense and a credit to the balance sheet account "accumulated depreciation." Depreciation for books and records may not be the same as taxable depreciation, resulting in an entry on Schedule M-1 of Form 1120S.
I hope this is helpful. Thanks again!