Overview
The NBX-972 is a high-density passive central distribution box for the heaviest commercial-vehicle and construction-machinery programs. It is the right specification when the circuit count outgrows the NBX-954 (~31 circuits) and the program needs a single high-density central block to handle body, chassis-auxiliary and aftertreatment-system fusing in one place. 65 fused circuits sit alongside 25 ISO relays and a 9-connector interface in a vented IP4x enclosure that natural-cools the relay pack — trading the IP65 seal of the smaller NBX boxes for the thermal headroom that a 25-relay pack needs. Cabin / under-dash / dry zones only; do not install in chassis-near or under-bonnet wet zones (see the IP67-sealed NBX-971 for those positions).
Engineering details
- 25× ISO relay positions — 8× ISO-mini (typical 30/40 A loads) and 17× ISO-micro (typical 15 A loads), populated per program
- 65 fused circuits in mixed formats — 4× J-case main-feed fuses for high-current branches, 60× mini-blade fuses (APM/APS-style) for individual circuits, 1× ATO standard-blade for a heavier auxiliary branch, plus 5× reserved positions for late additions; fuse ratings specified per program
- 1× flasher position — configurable for turn-signal flasher or wiper-interval timer per program
- Vented IP4x enclosure with a clear top cover — designed for natural cooling of a dense 25-relay pack; specify the smaller NBX-954 or the CAN-enabled NBX-952 when an IP65 seal is required
- 9-connector / ~148-pin harness interface — pin count by position: CON-A 2P / CON-B 16P / CON-C 18P / CON-D 18P / CON-E 21P / CON-F 16P / CON-G 18P / CON-H 18P / CON-J 21P. Current-production housings are TE/Tyco 968974 / 968975 series for the signal connectors plus a KET MG610557 main-power housing on CON-A; specific housing and terminal P/N confirmed against the customer harness drawing at quotation
- 9 – 32 VDC input — tolerates 12 V and 24 V vehicle architectures without re-spec
- UL94 V-0 flame retardancy and 10 – 500 Hz vibration durability — the box is designed for cabin / under-dash placement, not chassis-near or under-bonnet wet zones
- Mechanical envelope ~285 × 173 mm body (300.8 × 211 mm with mounting flanges); 77 – 85 mm housing height including connectors
Controlled circuit functions
The factory wiring map of the NBX-972 is sized for diesel-platform heavy commercial vehicles and construction machinery. Each function below maps to one fused branch — the relay-vs-fuse mix per branch is confirmed at quotation against the customer wiring diagram:
- Lighting: low / high beam, side & tail lamps, fog lamps, daytime running lamps, reverse lamps
- Driver feedback: turn-signal flasher, horn
- Wiper & HVAC: front wiper drive, climate blower
- Braking & safety: brake-circuit feed
- Powertrain auxiliary: hydraulic-fan control, fuel-pump control, ECU ignition / wake-up control
- Aftertreatment auxiliary: heater drive branch, heater delay-off branch (for diesel programs with aftertreatment systems that require timed power after engine shutdown)
The aftertreatment-related branches are what most clearly position the NBX-972 above the NBX-954 — modern diesel programs with aftertreatment systems typically need a timed-power branch to keep the heater warm for a defined period after engine shutdown, and that branch is hard to retrofit into the smaller boxes.
How it differs from NBX-952 and NBX-954
| Model | Density | CAN logic | Seal | Best for |
|---|---|---|---|---|
| NBX-972 | ~65 circuits / 25 relays | No (passive) | IP4x vented | Heavy truck / construction with aftertreatment functions |
| NBX-954 | ~31 circuits / 12 relays | No (passive) | IP65 sealed | Mid-density body wiring with separate BCM |
| NBX-952 | ~30+ circuits / 12 relays + flasher | Yes (program-specific) | IP65 sealed | One box for distribution + body-circuit logic |
For the architectural decision between a high-density vented PDB and a smaller IP-sealed one, see the junction vs fuse vs relay box guide. For chassis-near or wet-zone placement — which the vented NBX‑972 is not built for — use an IP67 sealed central PDB such as the NBX‑971; see the IP67 waterproof PDB notes.
Manufacturing & testing
Built under IATF 16949 with APQP project planning and a PPAP package available for OEM programs. Because the NBX-972 carries the highest circuit count in the NBX lineup, end-of-line testing covers every relay-actuation path and every fuse-circuit continuity branch before packaging; environmental validation and EMC pre-compliance screening in our in-house lab when the program requires it.
Related models & how to ask
Below this 65-circuit vented platform sits the IP54 body-cavity ladder — the NBX-953 (47-way), NBX-970 (42-way) and NBX-958 (32-way), with the general-purpose NBX-957 configured to the harness rather than pinned to a fixed circuit count. For mid-density passive distribution see the NBX-954 passive central distribution box. For a similar mid-density block with on-board CAN control logic see the NBX-952 CAN-enabled centralized PDB. For excavator and off-road machinery that needs a sealed, vibration-validated box mounted in the wet zone, use the IP67 NBX‑961 rather than this vented platform; see the excavator PDB notes. For the upstream main-feed protection block see the NBX-980 main battery fuse module. For the full lineup, see the Power Distribution family. To request drawings, sample units or a quote against your harness, please use the contact page.
