Custom Wire Harness Manufacturing in Mexico
Shelmex is a custom wire harness manufacturer in Mexico. We design and build complete wiring harnesses to your drawings and specifications for appliance, HVAC, industrial, and renewable energy brands across the United States and worldwide. Every harness is engineered around your product, so you get the exact build your application needs instead of a catalog part that almost fits.
What Makes a Wire Harness Different
A wire harness is a branched assembly that routes power and signals through a single product, bringing many wires, connectors, terminals, and protective sleeving into one organized network that follows the shape of your equipment.
A cable assembly, by contrast, is usually a single point-to-point run of cable with connectors on each end. If you need a simpler point-to-point build, see our cable assembly service.
Harness Types We Build
We build a wide range of harness types, each engineered for the demands of your product:
Modular harnesses
Plug and play connectors for fast assembly, used in smart appliances and control systems.
Main power harnesses
Carry primary current from the source to the equipment, for washers, electric ranges, and large air conditioning units.
Control and signal harnesses
Signal wiring for sensors and control panels, such as appliance boards, thermostats, and speed controls.
Fiber optic harnesses
Optical fiber instead of copper for high speed data, used in servers, data centers, and next generation HVAC and IoT devices.
High frequency harnesses
Tuned for high frequency signals with minimal loss, for remote controlled units and advanced sensors.
Compact harnesses
Extreme environment harnesses
Harness Features Built to Your Requirements
We build to the electrical and environmental demands of your product, including:
- High temperature resistance: wiring that holds up to heat in appliances and industrial equipment.
- Waterproof and water resistant construction: protection for units exposed to moisture.
- Oil and corrosion resistance: durability in harsh and industrial settings.
- Flexible and low voltage wiring: builds that route easily and handle low voltage needs.
- Custom lengths, connectors, and routing: every harness matched to your exact assembly.
Industries and Products We Wire
Our harnesses power products across several industries:
Home and commercial appliances
HVAC and climate systems
Air conditioners, inverter units, thermostat controls, and condenser wiring.
Fans and cooling
Solar and renewable energy
Harnesses for solar panels and renewable energy equipment.
Data and servers
Fiber optic harnesses for servers and data centers.
Industrial equipment
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Technical Capabilities and Specifications
Our engineering and production lines are set up to meet detailed technical requirements:
- Circuit range: harnesses from 2 to 300 circuits.
- Wire and cable range: cutting and stripping from AWG 32 wire to 535 MCM cable, in single and multiple conductors.
- Cable types: standard wiring plus ribbon cable and semi rigid coaxial cable for special jobs.
- Insulation materials: PVC, Teflon, Kynar, X-Link, Fiberglass, and DMD (Dacron/Mylar/Dacron).
- Harness builds: signal and low voltage harnesses and power cords.
- Quality methods: APQP, Lean manufacturing, PFMEA, SPC, and PPAP for new product launches.
- Testing: continuity and electrical testing on every build.
- Certifications: ISO 9001, C-TPAT, SAT IVA/IEPS, and IMMEX.
- Location: our plant sits about two hours from the Texas border, which shortens lead times to the United States.
Why Brands Choose Shelmex for Wire Harnesses
Companies across the United States and worldwide choose Shelmex because we deliver:
- Custom engineering, not catalog parts: we build from your drawings and samples.
- Quality you can audit: controlled processes, testing, and consistent workmanship.
- A flexible, agile partner: we adapt to your volumes and product changes.
- Manufacturing in Mexico: nearshoring advantages in cost, lead time, and proximity to the United States.
Frequently Asked Questions
Can you build to our drawings?
Yes. We work build to print, from your drawings, samples, or a reference harness.
What wire sizes and cable types can you handle?
Every harness is customizable to your specification. We routinely cut and strip from AWG 32 wire up to 535 MCM cable, in single and multiple conductors, and we also build with ribbon and semi rigid coaxial cable. If your project needs a different gauge, material, or connector, send us your requirement and we will confirm what we can build.