What should I check before buying a wire harness manufacturer?

A wire harness shop is not a surface-mount line with a few people watching machines. Check the trained hands, the tooling and the customer’s drawings. The general due diligence guide for electronics assembly leans toward SMT lines and component stock, so this page adds the questions that are specific to harness work.

Assemblers and bench know-how

Ask how long each assembler has been with the shop, who trains new people and who can read a complex drawing. If the owner or one senior person holds the know-how, plan for a long handover. Ask what happens to output if two skilled people leave in the same month.

Tooling, fixtures and drawings

List the crimp presses, applicators and cutting equipment, with their age and service history. Then ask which test boards and fixtures the customers own and which the shop owns. Customer-owned fixtures usually do not transfer; check the purchase agreement. Confirm that every drawing is current and that the shop controls revisions, so people build to the latest version.

Supply of copper and connectors

Find out who supplies wire, terminals and connectors, and whether any part is sole-sourced or specified by a customer. Ask how the shop handles shortages, and whether supplier terms depend on the current owner’s relationships.

Certifications and customers

• Ask which quality certifications the shop holds, ask to see the certificates, and ask how a change of owner affects each one.
• Ask the customers’ quality teams how they rate the shop, with the seller’s permission.
• Ask which accounts are tied to the owner personally.