Komatsu 800-7 Circuit Breaker Wiring Harness
Circuit Breaker Wiring Harness for Komatsu 800-7, OEM Quality Replacement Part #209-06-77311
Fitment
Fits the Komatsu 800-7. ECS lists 3 harness sections for this machine — see all 3 sections for the Komatsu 800-7 before you order, because the sections are not interchangeable.
Part number reference for the 209-06-77311
This harness is one part sold under one number. Suppliers and parts books write it differently — you may see it as 209-06-77311, 2090677311. 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 800-7
It runs from the breaker or hammer circuit on the boom to the control box in the cab, and takes more flexing than any other section on the machine.
What it connects
- Breaker solenoid to the control box — the on/off and flow commands for the attachment.
- Pressure and flow feedback to the controller — the inputs that stop the breaker from being over-driven.
What a failing Komatsu 800-7 harness looks like
| What the operator reports | Why the harness fits that symptom |
|---|---|
| Breaker will not fire, carrier runs fine | The attachment circuit, not the breaker itself. |
| Breaker works at some boom positions only | A run being stretched at the pivot. |
| Intermittent firing over a shift | Strand fatigue at the boom clamp or the quick coupler. |
| Fault appears after fitting a different attachment | Connector pinout on the attachment side. |
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
- 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.
- 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.
- 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.
Other harness sections for the Komatsu 800-7
Same type of harness on other machines
Product Description
High-quality circuit breaker wiring harness designed for Komatsu 800-7. This is a complete replacement harness that matches OEM specifications (Part #209-06-77311). All connectors and wiring are tested before shipping. Direct fit installation, no modification required. Made with durable copper wires and heat-resistant insulation for long service life in heavy-duty applications. Factory direct pricing with quality guarantee.
Why Choose ECS System Parts?
- Factory Direct: we build the loom — no middlemen
- In Stock Ready to Ship: most orders leave within 24 hours
- OEM Quality: made to the original drawing, connector for connector
- 1 Year Warranty: full coverage against defects
- Worldwide Shipping: DHL, FedEx, UPS, EMS
- Expert Support: WhatsApp +86-13714733803 — send us a photo of your old harness and we will confirm the section
Technical Specifications
| OEM Part Number | 209-06-77311 |
|---|---|
| Compatible Model | Komatsu 800-7 |
| Harness Type | Circuit Breaker Wiring Harness |
| Warranty | 12 Months |
Shipping Information
- DHL / FedEx / UPS / EMS worldwide
- Ships within 24 hours
- 3-7 days express, 7-15 days standard
- Tracking number provided
Return Policy
- 30-day return window
- Must be unused, original packaging
- Contact via WhatsApp for RMA authorization