Komatsu 1250-8R Fuel Injector Wiring Harness

Part number reference for the 6245-81-5320

This harness is one part sold under one number. Suppliers and parts books write it differently — you may see it as 6245-81-5320, 6245815320. They are all the same part; the number on the tag of your old harness is what settles the order.

If the tag shows a different number entirely, do not order by eye — send us a photo of it on WhatsApp and we will match it against the catalogue before anything ships.

Where this harness sits on the Komatsu 1250-8R

It sits under the valve cover on most engines, passing through the gasket or the head into the injector bores. It is the hottest electrical component on the machine.

What it connects

• ECM to each injector solenoid — the firing command for every cylinder, sequenced by the ECM.
• Injector to injector — a shared supply and return path, so one damaged section can affect more than one cylinder.

What a failing Komatsu 1250-8R harness looks like

These are circuit-level symptoms, not a diagnosis. The same behaviour can come from a sensor, an ECM input or a mechanical fault — the checks below are how you tell them apart.

How to confirm it is the harness before you buy

1. Compare the part number on the old harness. The number is printed on a tag or moulded into the main connector body. If it does not match, stop — stop here and send us a photo, because two sections of the same machine are not interchangeable.
2. Resistance test the suspect run. Disconnect both ends and measure end to end. A reading that is far above the others in the same loom means broken strands; a reading to ground means chafing.
3. Wiggle test under load. Back-probe the circuit with the machine running and flex the loom by hand along its length, especially at clips and at the cab or boom entry. If the meter or the fault jumps, you have found the run.

Where this part sits in the Komatsu 1250-8R range

ECS lists 2 harnesses in this section group for this machine. At $269.50 the 6245-81-5320 is the most expensive, against a range of $247.50 to $269.50. Stock on hand: 3.

The closest part in price is 6245-81-9110 at $247.50 — $22.00 apart. The two are separate looms; the tag on your old harness settles which one you need.

We photographed this exact unit: 8 images on this page are of the 6245-81-5320 we have in stock, not a catalogue picture. Price tracks section size and how much of the loom is enclosed, not condition — every part we list is new build.

Other harness sections for the Komatsu 1250-8R

All 4 harness sections for the Komatsu 1250-8R →

Same type of harness on other machines

• 147-1771 — Caterpillar 140H Engine Injector Wiring Harness
• 305-4891 — Caterpillar 312D Injector Wiring Harness
• 305-4893 — Caterpillar 320D Injector Wiring Harness
• 375-8407 — Caterpillar 323D C6.6 Injector Wiring Harness
• 637-2653 — Caterpillar 336E Fuel Injector Wiring Harness