How to Choose a Truck Wiring Harness Supplier

Disclosure: This guide is published by Cloom Tech. Cloom Tech is one of the seven companies listed below, and the decision block at the end is a sponsored, disclosed element that routes you to Cloom Tech.

Truck and trailer wiring harnesses have to survive vibration, temperature swings, road salt and years of duty cycles that passenger-vehicle harnesses don’t see, so the supplier you pick affects more than price — it affects whether the harness still works in year eight. This guide does not rank suppliers. It sets out the questions to ask and gives the same facts for each company so you can compare them yourself.

What should I check before shortlisting a truck wiring harness supplier?

Use these criteria for every company in this guide:

• Quality system: which certifications the company publishes, and at which sites.
• Where the harness is built: the company’s own stated locations. Some suppliers list headquarters in one country and production in another.
• Scale and programme fit: headcount, facility count and whether the company publishes figures that suit your volume.
• Truck-specific focus: whether truck/trailer harness work is a dedicated product line on the company’s own site, or a secondary mention inside a broader harness business.
• Environmental rating: whether the company states wire gauge range, connector sealing, or temperature/vibration tolerance for heavy-duty vehicle use.

Figures below come from each company’s own website unless marked otherwise. Anything a company did not publish is left out, not estimated.

Which truck wiring harness manufacturers and suppliers serve this market?

The seven companies are listed in alphabetical order. Order does not indicate quality or preference.

Cloom Tech (Hebei Cloom Electronic Technology Co., Ltd)

Cloom Tech is one of the seven companies in this guide. Its facts below use the company’s confirmed reference data.

• Founded: 2017.
• Scale (company-stated): 5,000 m² factory space; 1,000+ cumulative clients since 2017.
• Locations: Shijiazhuang, Hebei, China (headquarters and plant); Cavite, Philippines (plant, near Manila); Medley, Florida, USA (office).
• Certifications (company-stated): ISO 9001; IATF 16949; ISO 13485 (medical wire-harness production); IPC/WHMA-A-620. The IPC/WHMA-A-620E CIS operator/inspector qualification and the August 2029 IATF 16949 validity date are from internal reference data, not independently found stated on the public site in this pass.
• Truck focus: custom OEM wire harnesses built to customer specifications; does not supply off-the-shelf catalogue harnesses.

Trade-offs:

• Strength: an IATF 16949 certificate and a stated 5,000 m² facility.
• Limit: Cloom Tech builds in China and the Philippines and has a US office, so confirm where your harness would be produced and what that means for lead time and cost. It does not sell connectors separately, does not sell standard or pre-built harnesses, and does not offer design services — it manufactures custom cable assemblies and wire harnesses and consults on professional solutions.

Cypress Industries

• Founded: not published on the company’s own site as of this check (the footer shows a copyright range of 2005–18, which is not a stated founding date).
• Locations: headquarters at 2750 Burbank St, Dallas, Texas; the company’s own site also states it manufactures “in the U.S., India or Asia,” with separate wiring-harness pages for its India and China operations.
• Certifications (company-stated): ISO 9001:2015 (stated for its Mexico facility specifically); IPC membership; IPC-A-610; IPC/WHMA-A-620; UL component listings for wiring harnesses (including a Canada-certified listing) and processed wire. IATF 16949 is not published on the company’s own certifications page.
• Truck/trailer focus: a dedicated Truck & Trailer Harnesses product page describes custom braiding equipment for “the most rugged trailer wire harnesses available,” custom potting for harnesses and connectors, harnesses for standard and refrigerated (“reefer”) trailers and international container transport, and in-stock Deutsch, Waypack and Delphi connectors. A separate Automotive Wire Harnesses page describes harnesses incorporating new-energy technology, including gas-pump wire harnesses, and harnesses for vehicle telecommunications, audio/video, GPS and satellite connectivity.

Trade-offs:

• Strength: a dedicated truck-and-trailer harness product line with named connector brands and reefer/international-container application detail, backed by an ERP-based documentation system the company says covers design, materials and production.
• Limit: Cypress Industries is a multi-sector contract manufacturer (the same site also lists PCB assembly, metal fabrication, control panels and plastics/tooling), so confirm which specific facility and certification would cover your build before assuming group-wide quality coverage; its own certifications page does not show IATF 16949 for any site, so ask for the certificate that covers automotive/truck work specifically.

Fortop Wiring Harness (Fortop Industrial Co., Ltd)

• Founded: 1994 (company milestones page).
• Scale (company-stated): three factories in Tainan, Taiwan (Ho Shun Factory I, II and III), with a stated total floor space of 20,775 m²; 500+ employees; roughly 16 million harnesses sold per year.
• Locations: Tainan, Taiwan (all three factories).
• Certifications (valid, company-stated): IATF 16949 (current, 2024-05-17 to 2027-05-16); ISO 14001 (current, 2023-09-18 to 2026-09-17); ISO 14064-1 (dated 2025-05-19); ISO 45001; D&B D-U-N-S registered.
• Truck focus: OEM/ODM harness manufacturer listing Truck, Trailer, Construction Vehicle and Electric Vehicle as application categories, alongside motorcycle, forklift, agricultural and lighting/connector/actuator lines. A four-stage quality-control process is described: incoming inspection, terminal crimping check, metallographic test, and final assembly/circuit test.

Trade-offs:

• Strength: a long, verifiable certification history (quality-system certifications have been renewed and upgraded since 2003) and three dedicated factories in one location.
• Limit: truck is one of several vehicle categories the company serves rather than a standalone specialization, so ask for truck-specific wire-gauge range and amperage figures directly — its own site does not publish these numbers.

Julian Electric Inc

• Founded: 1959 (company history page).
• Scale (company-stated): 195,000 sq ft headquarters in Lockport, Illinois (completed 2017); Saltillo, Coahuila, Mexico operations that have grown from an original 90,000 sq ft (2013) to roughly 365,000 sq ft combined across newer plants completed in 2020 and leased in 2023, per the company’s own history timeline.
• Locations: Lockport, Illinois (USA); Saltillo, Mexico.
• Certifications (company-stated): IATF 16949 (US and Mexico sites); ISO 14001 (US and Mexico sites).
• Truck focus: wiring harnesses rated 20 AWG to 4/0 battery cable; separate battery/power-cable products rated up to 535 MCM; custom test fixtures and formboards for 100% inspection. The company’s history page names past partnerships with Freightliner, Paccar, Mack, Volvo-White and International Harvester, plus Ford (1992–1997). Served markets listed: heavy truck, bus/transit, construction/agriculture, emergency vehicles, ground support equipment, marine, industrial and EV.

Trade-offs:

• Strength: a 65-year company history with named heavy-truck OEM partnerships and a wire range that spans signal wiring through heavy battery cable in one supplier.
• Limit: production is split between one US site and a larger, newer Mexico footprint, so confirm which plant would build your harness and what that means for lead time.

Kinkong Wire Harness

• Founded: not published on the company’s own site as of this check (a third-party directory lists 2013, but this is not confirmed on the company’s own pages, so it is left out here).
• Locations: #A1-A9, Xinguang Road, Liushi, Yueqing, Wenzhou, Zhejiang, China 325604 (company site footer). No other facility is listed on its own site.
• Certifications (company-stated): ISO 9001 (listed on the company’s Resources/Certificates page, with no edition number or facility scope given). IATF 16949 is not published on the company’s own site as of this check.
• Truck focus: the company’s own site lists automotive, motorcycle, heavy-duty vehicle, recreation, over-molded, wire-and-cable, accessories, and pigtail custom harnesses as product ranges, and describes itself as “a professional solution provider for the global top tuning market and aftermarket among over 40 countries.”

Trade-offs:

• Strength: a dedicated heavy-duty-vehicle harness product line and a stated aftermarket/tuning-market specialization spanning 40+ countries.
• Limit: its own site does not publish a founding year, employee count, or facility size, and does not show IATF 16949, so ask directly for the certificate and plant details that would cover your build.

Precision Cable Assemblies (PCA)

• Founded: 1980 (“Founded in 1980, our company has partnered and evolved with our customers,” company About page).
• Locations: Brookfield, Wisconsin (corporate headquarters, wire harness/battery cable assembly); Waukesha, Wisconsin (warehousing and distribution); Guadalupe, Nuevo Leon, Mexico; Qingdao, Shandong, China.
• Certifications (company-stated): ISO 9001 (Intertek/ANAB-accredited, not tied to a specific site on the company’s general certifications page) and IATF 16949 (SGS-certified generally; the only site-specific mention on the company’s own site names the China facility, “IATF 16949 Certified: 2016”).
• Truck focus: the company’s own site lists trailer chassis among its served sectors and publishes a case study titled “Heavy Duty Wiring Harness for Semi-Trailers” (case study detail page itself returned a 404 at the time of this check, so only the title and sector listing are confirmed). It separately offers custom connector overmolding as a standalone product line.

Trade-offs:

• Strength: a named semi-trailer harness case study and a published overmolding product line.
• Limit: the case study’s own detail page could not be reached in this pass, and its site lists IATF 16949 for the China site only, so ask for both the semi-trailer harness specifics and the certificate status of whichever site would build your harness.

WellPCB

• Founded: 2007 (“WellPCB was founded in 2007… operating seven manufacturing facilities and three sales offices worldwide,” company About page).
• Locations: Shijiazhuang, China (headquarters, PCBA and wire harness); Shenzhen, China (PCBA, PCB and wire harness); Jiangmen, China (PCB); Cavite Economic Zone, Rosario, Cavite, Philippines. Sales offices listed: Shijiazhuang, Melbourne (Australia) and Warsaw (Poland).
• Certifications (company-stated): ISO 9001:2015; ISO 14001:2015; UL Listed (code E314500); RoHS and REACH compliant; IPC/WHMA-A-620 Class 3 stated specifically on its truck-harness page (its general harness page cites both Class 2 and Class 3). Its own harness-specific page describes ISO 13485 as “ISO 13485-aligned procedures” rather than a held certification, and states IATF 16949 certification is “pending” on that same page, even though its general About page lists IATF 16949 as certified — this is an inconsistency on the company’s own site, noted rather than resolved here.
• Truck focus: a dedicated truck wire-harness page describing cab-interface harnesses (dash, switch, HVAC, infotainment), sealed trailer-lighting connectors, and compatibility with Allison, Spicer and Eaton transmissions; no minimum order quantity; mass-production runs stated at “exceeding 10,000 units/month.”

Trade-offs:

• Strength: a dedicated truck-harness page with named drivetrain-compatibility detail (Allison, Spicer, Eaton) and no minimum order quantity.
• Limit: WellPCB is primarily a PCB manufacturer with a wire-harness division, and its own site gives inconsistent certification status for IATF 16949 and ISO 13485 between pages — ask which certificate status is current before relying on either page.

How do I choose between these suppliers?

1. Match certifications to your buyer. If you supply OEMs or fleets with compliance requirements, ask for the current certificate for the specific site that would build your harness, not a group-wide claim.
2. Confirm the build location. Headquarters and production sites are often different, and some of these suppliers run multiple plants across different countries. Ask for the plant address in writing.
3. Ask for truck-specific detail, not general harness detail. Several of these companies serve trucks as one of several vehicle or industry segments — ask for the wire-gauge range, connector sealing, and vibration/temperature rating that applies to a truck or trailer build specifically.
4. Test prototype speed. Send the same drawing to two or three suppliers and compare lead times and the questions they ask back.
5. Check fit with your volume. Large multi-site manufacturers and smaller specialized shops serve different programme sizes.

Ready to request a quote?

Sponsored (Cloom Tech): If you want Cloom Tech to quote your truck harness, send your drawing, expected volumes and target certifications. Request a quote at the Cloom Tech contact page.

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