Technical guide
Connector types on 24V commercial vehicles.
Every lamp on a commercial vehicle terminates in a connector. The choice between Deutsch, SuperSeal, AMP, JST, Bulgin or one of the dozen other options is not cosmetic — it determines whether a retrofit survives five years of jet-washing, road salt and vibration. This guide maps the main families, what each is good at, and which ones belong nowhere near a commercial vehicle.
Laatst bijgewerkt 24 april 2026
Deutsch DT / DTM / DTP — the standard
The Deutsch Connector Co. DT series is the de-facto standard for commercial-vehicle wiring harnesses. It comes in three sizes:
- **DT**: 0.5–2.5 mm² wire, 13A per pin, 2 to 12 contacts per connector — the workhorse - **DTM**: 0.35–1.0 mm² wire, 7.5A per pin, 2 to 12 contacts — for signal-level runs - **DTP**: 2.5–4 mm² wire, 25A per pin, 2 to 4 contacts — for high-current runs (motors, relays)
All three share a wedge-lock retention system that's tool-serviceable without destroying the connector. IP67 sealing out of the box, IP69K with silicone grease. Every professional retrofit we ship uses a Deutsch pigtail.
SuperSeal 1.5 — the economical second choice
TE Connectivity's SuperSeal 1.5 series is common on European OEM vehicle harnesses — MAN, Mercedes, Iveco use it extensively. Wire range 0.35–1.5 mm², 14A per pin, 2 to 6 contacts.
The seal is via gasket O-rings inside the housing. IP67 when mated; less forgiving than Deutsch when partially disconnected. Used where cost matters more than absolute robustness; fine for cab-internal signal runs, riskier on a trailer.
SuperSeal pins are not interchangeable with Deutsch. Mixing the two in one installation means stocking both crimp dies.
AMP / TE Junior-Power Timer
Junior-Power Timer (JPT) is the legacy connector on older European trucks — pre-2015 Volvo, pre-2010 Scania, older DAF. Wire range 0.35–2.5 mm², up to 17A per pin, 2 to 25 contacts.
Not inherently weatherproof; the weatherproof variant (MCP-5-HD) has a gasket seal but needs correct gland nuts and the right wire diameter. Plenty of old installs use JPT badly — original OEM harnesses are usually fine, retrofit work is mixed.
Our recommendation: if you're replacing an original JPT connector during a retrofit, swap the whole end over to a Deutsch DT of equivalent pin count. One-and-done reliability upgrade.
What to avoid on a commercial vehicle
Some connectors that work fine on passenger cars are a bad idea on trucks:
- **JST XH / SM** — bare, zero sealing, pins corrode in weeks on an exposed installation. Fine inside a cab dashboard, useless elsewhere. - **Molex Mini-Fit** — hobbyist-grade, no waterproof variant, retention clip breaks on vibration. - **"Universal" barrel connectors** (2.1/5.5 mm DC jacks) — the opposite of what you want; no retention, no seal. - **Scotch-locks** — fail within a winter on anything that sees water.
If the lamp comes with one of these as a factory pigtail, cut it off and fit a Deutsch DT. The extra cost is ~€5 and buys you five years of reliable connection.
A good connector costs €3 more than a bad one. The callout to replace a bad connector in February costs €180. Buy the Deutsch.
Pigtails and inline splices
When you need to extend or splice a sealed loom without the original crimp tool, the options are:
- **Heat-shrink adhesive-lined butt splices** — fast, reliable, tool-free (just a heat gun). Not field-serviceable but rarely fails. - **Deutsch Modular connector** — add a DT-2 inline, splice via Deutsch pins. Slower but field-serviceable. - **Glued crimp terminal + heat-shrink** — works in a pinch but only as reliable as the crimper you used.
For a professional workshop, stocking a Deutsch DT-4 / DT-6 inline pair plus a Uniseal stripper-crimper covers 90% of retrofit splices.