Wrong parts delivered: what to check first and how to send them back

Wrong parts: compare three numbers before anything else

If the label doesn’t match the order, the seller picked or packed the wrong item. If the label matches the order but not the catalog, the number was wrong when it was ordered, either from a guess or from the seller’s own catalog. If all three match and the part still looks different, it may not be wrong at all.

RockAuto, the online parts retailer, says part makers may use designs that differ from the original equipment to cut cost, improve performance or cover more cars, and that makers sometimes change a part slightly without changing its number. Its advice is to report the part only when the difference goes beyond cosmetic and the part won’t work on your car.

Photograph the label, the part and the packaging before you do anything else. If you end up returning it, the photos back up your case.

Revision letters and superseded numbers

A different suffix doesn’t make a part wrong, and a newer suffix doesn’t make it right. A 2018 Porsche technical bulletin for the 2017 Panamera’s PASM control unit shows why. The base number is 971.907.553. Suffix AJ, hardware version H20, replaces AA and AC, while AD, hardware version H12, replaces AB. The same bulletin says a unit that stops responding during programming must be replaced with the latest number listed for that car.

So check the chain in the catalog rather than assuming the highest letter fits. Our guide to parts supersession explains how a number moves on, and the Porsche PET catalog shows the current number for a Porsche VIN.

Don’t fit it to find out

RockAuto tells customers not to try to make a part fit, won’t accept returns of parts that have been installed or modified, and isn’t responsible for any costs beyond the price of the part.

Electrical parts are stricter. One online genuine Ford parts store states that electrical and special-order parts are not returnable at all. OEMBimmerParts, an online BMW parts store, says electrical parts can’t be returned for any reason once the packaging is opened, although it says they carry a two-year replacement warranty. Under a rule like that, opening the bag ends the return, so read the label through the packaging first.

Return windows, restocking fees and who pays shipping

There is no standard. Each seller sets its own terms, and the differences are large. Read them before you buy, since special-order and electrical exclusions bite hardest when you are least sure of the number. Four examples, as the sellers state them:

• RockAuto: 30 days for a refund of the part price, complete and in the original, unmarked manufacturer’s packaging. You pay return shipping unless you received a different part number from the one you ordered, it arrived defective, or the maker confirms RockAuto’s catalog was wrong.
• The online Ford parts store: return requests within 14 days of receipt, a 20% restocking fee on eligible returns, and return shipping paid by the customer.
• OEMBimmerParts: 45 days from the order for new items still sealed in the factory packaging. The customer pays return shipping, and the store supplies a label for items that arrived damaged.
• eBay: an item that doesn’t match its listing can be reported within 30 days of delivery, or within the seller’s longer return window, and the seller pays return shipping.

Cores: keep the old part until the right one is on

If the new part carried a core charge, the old part is worth money. RockAuto refunds core deposits for cores returned within six months, complete, for the same vehicle application, in the box the new part came in. The core doesn’t need to work, but it earns nothing if it is smashed or rusted solid. OEMBimmerParts gives no core credit for a core that comes back without the original manufacturer’s box.

Don’t send the core back in the box of a part that was wrong, and don’t throw the old part away until the correct replacement is fitted and working.

Stop the next one

Most of this is avoidable. Look the number up by VIN before you order, write the VIN and the number on the order, and check the label against both when the box arrives. Our guide to cutting wrong-part returns sets out the routine for a workshop, and the real cost of a wrong part adds up what one return costs beyond the refund.