Short answer
DENUE lists 98 wire harnesses and electrical parts plants with 11 or more staff in Aguascalientes, Guanajuato, Querétaro and San Luis Potosí. 90 have 51 or more staff, and 63 of those match an IMMEX program on exact name and postal code. Guanajuato has the most, with 48. Each plant still needs its own checks.
Key facts
- Activity codes (SCIAN)
- 336320
- Plants, 11+ staff
- 98
- Data
- INEGI DENUE bulk files, 25 Sep 2026; IMMEX directory, August 2026 edition
About wire harnesses and electrical parts
Harness plants build cable assemblies and electrical parts for vehicles. They are labour intensive and skewed large: most of the plants below have 251 or more staff.
The numbers by state
| State | Plants, 11+ staff | With 51+ staff | With an IMMEX match |
|---|---|---|---|
| Guanajuato | 48 | 44 | 32 |
| Querétaro | 21 | 21 | 15 |
| San Luis Potosí | 19 | 18 | 13 |
| Aguascalientes | 10 | 7 | 5 |
| Four states | 98 | 90 | 65 |
| Staff band | Plants |
|---|---|
| 11 to 30 | 4 |
| 31 to 50 | 4 |
| 51 to 100 | 4 |
| 101 to 250 | 12 |
| 251 or more | 74 |
What to ask a wire harness supplier
Registries show that a plant exists and exports. These questions cover what they cannot.
- The workmanship standard they build to, such as IPC/WHMA-A-620.
- Electrical testing: is every harness tested, and how is the data kept.
- Crimp validation and connector sourcing.
- Traceability from wire lot to finished harness.
- Which customers already run their programs there.
Checks before you approach a plant
- Confirm the plant in DENUEName, address, activity code and staff band.
- Check its IMMEX programStatus and type, matched on legal name and postal code.
- Search the SAT 69-B listBy RFC where you have it, otherwise by exact name.
The verification guide explains each step and where it stops.
Frequently asked questions
How many wire harnesses and electrical parts plants are in the Bajío?
INEGI’s DENUE lists 98 wire harnesses and electrical parts plants with 11 or more staff across Aguascalientes, Guanajuato, Querétaro and San Luis Potosí. 90 of them have 51 or more staff. Testigo counted these from INEGI’s bulk files on 25 September 2026.
Which Bajío state has the most wire harnesses and electrical parts plants?
Among the four states Testigo counted, Guanajuato has the most wire harnesses and electrical parts plants in DENUE, with 48 of 98, followed by Querétaro (21). Plants elsewhere in Mexico are outside Testigo’s pilot, and counts are establishments in INEGI’s directory as of 25 September 2026.
Do wire harnesses and electrical parts plants in the Bajío export under IMMEX?
Some do. 65 of the 98 plants match an IMMEX program on exact name and postal code, and 63 of the 90 with 51 or more staff. A plant with no match may still export through a shelter company’s program, so ask which entity holds it.