# Fitment Validation Matrix

## Input Combinations

| Case | Year | Make | Model | VIN | Expected Outcome |
|-----:|------|------|-------|-----|------------------|
| 1 | ❌ | ❌ | ❌ | ❌ | Reject: input required |
| 2 | ✅ | ❌ | ❌ | ❌ | Reject |
| 3 | ❌ | ✅ | ❌ | ❌ | Reject |
| 4 | ❌ | ❌ | ✅ | ❌ | Reject |
| 5 | ✅ | ✅ | ❌ | ❌ | Reject |
| 6 | ✅ | ❌ | ✅ | ❌ | Reject |
| 7 | ❌ | ✅ | ✅ | ❌ | Reject |
| 8 | ✅ | ✅ | ✅ | ❌ | Evaluate via YMM |
| 9 | ❌ | ❌ | ❌ | ✅ | Evaluate via VIN |
| 10 | ✅ | ❌ | ❌ | ✅ | Evaluate via VIN |
| 11 | ❌ | ✅ | ❌ | ✅ | Evaluate via VIN |
| 12 | ❌ | ❌ | ✅ | ✅ | Evaluate via VIN |
| 13 | ✅ | ✅ | ❌ | ✅ | Evaluate via VIN |
| 14 | ✅ | ❌ | ✅ | ✅ | Evaluate via VIN |
| 15 | ❌ | ✅ | ✅ | ✅ | Evaluate via VIN |
| 16 | ✅ | ✅ | ✅ | ✅ | Evaluate via VIN (VIN wins) |