AVL, AML (approved manufacturer list), BOM, parts list, harness BOM
For a wire harness, the BOM is long and unforgiving. Every housing, every terminal, every wire seal, every cavity plug, every secondary lock, every metre of wire, every length of conduit and every clip is a line with its own MPN and its own quantity. The build cannot start until every line is covered, which is why a five-cent cavity plug and a control-module connector have exactly the same power to stop a line.
The AVL sits on top of it. OEM and Tier 1 programmes fix approved manufacturers per line, and often approved sources too. That constraint is what makes shortages painful: the buyer cannot simply take an equivalent part from an unapproved maker, because the approval, not the function, is what the programme requires.
This is the practical distinction between an AML, which approves the manufacturer of the part, and an AVL, which approves who you may buy it from. An independent distributor can supply an AML-approved part where the buyer's procurement rules allow non-franchised sourcing, and many do allow it precisely for shortage, obsolete and end-of-life cases, with additional verification requirements.
Harness Code works from the BOM line that is blocked, sources against the approved manufacturer where the part exists, and where it does not, proposes an alternative with the differences stated so the buyer can take it through their own approval process.
Related terms
Manufacturer Part Number (MPN)
A Manufacturer Part Number (MPN) is the unique code a component maker assigns to one exact product variant. In automotive connectivity, the MPN fixes housing, cavity count, keying, colour and plating, so two parts with different MPNs are not interchangeable even if they look identical.
Allocation and lead time
Allocation is when demand for a component exceeds supply and the manufacturer rations output across customers instead of quoting freely. Lead time is the interval between placing an order and receiving it. When a part goes on allocation, its lead time stretches and stops being a promise.
Obsolete / End-of-Life (EOL) component
An obsolete or End-of-Life component is one the manufacturer has stopped producing. It usually passes through an NRND warning and a last-time-buy window first, after which the only remaining supply is existing channel stock, excess inventory, or a qualified alternative.