Description

Hitachi Sumitomo ZAXIS170W-3, ZAXIS190W-3 Wiring Diagram

You’re staring at a bundle of wires from a ZAXIS190W-3 that someone hacked into last week. The aftermarket print you grabbed from some forum shows a different connector layout. Now you’ve got a no-start and a potential fire hazard if you guess wrong. I’ve seen it too many times. That’s why I only use factory Hitachi Sumitomo ZAXIS170W-3, ZAXIS190W-3 Wiring Diagram documents when I’m tracing circuits on these wheeled excavators. This 14-page OEM PDF gives you the actual pin numbers, wire colors, and connector views—not some redrawn approximation.

Front Attachment Harness: Reading the OEM Schematic

The first section in this manual covers the ZAXIS170W-3/190W-3 FRONT ATTACHMENT HARNESS (OPTIONAL). I’ve seen techs skip this because it’s labeled “optional,” but that harness controls the coupler and bucket circuits. The schematic shows both attachment connectors (ATT1, ATT2) with Sumitomo 6189-0031 housings. Wire sizes are listed in mm²—0.5 mm² for all four circuits—and the color codes follow Hitachi’s standard: G (green), L (blue), P (pink), W (white). On page 1 you’ll find the exact from‑to pin mapping so you can verify continuity without backprobing the wrong cavity.

Does This Manual Cover the Selector Valve?

Yes. Page 3 shows the ZAXIS140W-3/170W-3/190W-3 SELECTOR VALVE / SECONDARY PILOT RELIEF SELECTOR HARNESS (OPTIONAL). This is the circuit that controls the secondary pilot relief and the selector valve itself. The pinout lists 14 wires, including the 0.5 mm² L wire for the RELIEF SOL-2 circuit and the 1.25 mm² L wire feeding the SERECT SOL-2. If you’re chasing a slow swing or weak auxiliary flow, you need this page—not a guess. The diagram includes connector views for Yazaki 7222-7544-40 and the 2SPEED/H junction block.

14 Pages of Factory Wiring Data

Every page is a Harness-specific schematic, not a generic block diagram. You get: Flow Rate Selector Harness, Assist Harness (1 and 2), Boom Bottom Pressure Sensor Harness, Overload Alarm Harness, Grip Extension Harness, Heater Seat Harness, and Auto-Cruise Harness. Each one lists circuit numbers, wire sizes, colors, and termination points. For example, the Boom Bottom Pressure Sensor Harness on page 4 gives you the 5V supply (wire 270, 0.3 mm² WG) and ground (wire 73, 0.3 mm² W) to the pressure sensor connector. That kind of detail stops electrical fires before they start.

Understand the Harness Routing Before You Cut a Wire

When I’m working on a ZAXIS170W-3 that has an aftermarket alarm system added, I pull this manual first. The overload alarm harness section shows exactly which taps were designed for optional equipment. You can see where the factory left splice points—like the 100 mm cot (cable tie) locations marked on the assist harness drawings. That tells me where the harness is supposed to be secured so I don’t twist a wire under the cab floor. This is the kind of mechanical engineering detail that aftermarket reprints lose in translation.

Selector Valve / Secondary Pilot Relief Harness: What the Manual Shows

Back to page 3 for a moment. That section includes a note: “Attach to Vol. No.: TTCEB-E-00, TTCGB-E-00.” Cross-referencing the volume numbers means you can verify which service bulletin applies to your machine. The schematic uses Yazaki connectors (7323-1424-40) with specific assembly numbers (7322-9623-40). If you need to order a replacement pigtail, you’ve got the part number in hand. Don’t rely on a third-party catalog; this is the official Hitachi Sumitomo data.

Is this the full service manual?

No. This is strictly the wiring diagram pack—14 pages of harness schematics only.

Can I use this to trace a short circuit on a ZAXIS190W-3 that has a non‑factory radio installed?

Yes, but you need to understand that this manual covers only the factory optional harnesses. Aftermarket add-ons will not appear in these diagrams. Start by identifying which OEM harness the aftermarket wire taps into—for example, if the radio is powered from the assist harness, you’ll find the assist harness schematic on page 5. The diagram shows the ASSIST1 and ASSIST2 connectors with wire colors (411, 424, 417, 418) and their routing. Compare those colors to what you see at the fuse block. If the wire gauge doesn’t match or the color is missing, you’ve found your problem. Also check the ground paths: the assist harness sub-connector (Yazaki Z04F-GY) has explicit pin assignments—verify continuity there before replacing any modules.

You don’t need to be a dealer tech to use this. If you’ve got a multimeter and know how to read a pinout, you can sort out intermittent faults and harness damage on these Hitachi Sumitomo machines. Pair it with a Hitachi Sumitomo ZAXIS-3 Series Electrical Schematic Review for the bigger electrical picture, or grab the Hitachi Sumitomo ZW310 Wiring Diagram – 17-Page Factory Schematic if you’re also working on wheel loaders. For older machines, the Hitachi Sumitomo ZAXIS160-3 ZAXIS180-3 Wiring Diagram – 16-Page Factory OEM covers similar chassis. And if you need to brush up on the fundamentals, read up on Automotive Wiring or Automotive Wiring on Wikipedia to understand how the color codes and connector standards apply. Access the Factory Manual now and keep it on your shop tablet—it’s a lot cheaper than buying a new ECM because you wired the pressure sensor backward.