Caterpillar 420E Excavator Wiring Harness — All 4 Sections
The Caterpillar 420E uses 4 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 |
|---|---|---|
| Engine Harness | Intermittent misfire or a dead cylinder | Engine Harness group |
| ECU / Controller Harness | Controller dead or rebooting | ECU / Controller Harness group |
| Instrument & Interior Harness | One instrument or accessory dead | Instrument & Interior Harness group |
Engine Harness 2 parts
It runs inside the engine compartment, clipped along the block and head and routed past the front cover. On most machines it is the longest harness on the engine side and the one closest to exhaust heat.
| Part # | Description | Price | Stock |
|---|---|---|---|
| 263-9484 | Engine Wiring Harness | $300.00 | In stock |
| 308-2266 | Engine Wiring Harness | $273.90 | In stock |
ECU / Controller Harness 1 part
It sits between the controller box and the machine harness, in the cab or behind a panel, and carries the low-level inputs and outputs the controller reads.
| Part # | Description | Price | Stock |
|---|---|---|---|
| 290-6751 | Engine ECU Wiring Harness | $1692.90 | 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 |
|---|---|---|---|
| 246-8051 | Cab Interior Wiring Harness | $1098.90 | In stock |
Not sure which of the 4 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.