Komatsu 1250-7 Excavator Wiring Harness — All 5 Sections
The Komatsu 1250-7 uses 5 separate harness sections that ECS builds. They are not interchangeable: the part number on your old loom decides which one you need. Below they are grouped by where each section sits on the machine, with the part numbers and the symptoms that point to each group.
Which section do I actually need?
Start from the fault, not from the part name. Find the symptom the operator reports, then open that group.
| Section | First symptom to look for | Group |
|---|---|---|
| External Harness | Several circuits dead after rain or a wash | External Harness group |
| Alternator Harness | Battery not charging, warning on | Alternator Harness group |
| Pump Control Harness | Power derate with no hydraulic leak | Pump Control Harness group |
| Instrument & Interior Harness | One instrument or accessory dead | Instrument & Interior Harness group |
| Aftertreatment Harness | Regeneration will not start | Aftertreatment Harness group |
External Harness 1 part
It is the outside harness on the machine body — exposed to rain, wash-down, mud and UV. On most machines it is the section most often replaced.
| Part # | Description | Price | Stock |
|---|---|---|---|
| 21N-06-33741 | External Wiring Harness | $8650.00 | In stock |
Alternator Harness 1 part
It is the short charging-circuit harness between the alternator, the battery and the machine harness.
| Part # | Description | Price | Stock |
|---|---|---|---|
| 6240-81-9151 | Alternator Wiring Harness | $471.90 | In stock |
Pump Control Harness 1 part
It runs in the pump compartment between the pump controls and the machine harness.
| Part # | Description | Price | Stock |
|---|---|---|---|
| 21N-06-33541 | Main Pump Sensor Wiring Harness | $250.00 | In stock |
Instrument & Interior Harness 1 part
It sits inside the cab, behind the trim, feeding the instruments and controls the operator sees and touches.
| Part # | Description | Price | Stock |
|---|---|---|---|
| 21N-06-33154 | Interior Wiring Harness | $977.90 | In stock |
Aftertreatment Harness 1 part
It runs from the aftertreatment unit — DPF, SCR or DOC — back to the engine ECM, along the frame or the engine bay, close to high heat.
| Part # | Description | Price | Stock |
|---|---|---|---|
| 21N-06-33510 | Exhaust Temperature Sensor Wiring Harness | $1000.00 | In stock |
Not sure which of the 5 sections is yours?
Send a photo of the tag on your old harness to WhatsApp +86-13714733803 and we will confirm the part number against this list before you order. Getting the section wrong is the most common reason a replacement does not fit.