How to read a car part number
The single most reliable way to buy the right part is to match the number on the one you're replacing. It cuts through trim, engine and facelift guesswork in one step.
Where to find it
Most parts carry a number moulded, printed or stamped somewhere on the body of the unit — on a label, cast into plastic, or etched into metal. Clean off the grime and look on flat faces and around mounting points. Photograph it before it goes in the bin.
What the number tells you
On many European cars the number encodes the platform, the system and a revision. You don't need to decode it — you need to match it. Sellers list part numbers precisely because buyers search for them, so a number search often takes you straight to the exact part.
Watch for supersessions: a part number is sometimes replaced by a later revision that fits the same cars. If a seller lists a different number and says it 'replaces' yours, that's usually fine — but confirm it if you're unsure.
Cross-checking
Got a number but not sure it's yours? Cross-check it against your registration or engine code, or ask the seller to confirm it fits your exact car and year. Two independent checks that agree is as certain as you can be short of test-fitting.