Caterpillar 390F Boom Headlight Wiring Harness
Boom Headlight Wiring Harness for Caterpillar 390F excavator. OEM part 399-0808. Direct replacement.
Fitment
Fits the Caterpillar 390F Excavator. This is the only section ECS currently lists for this machine, so confirm the part number on your old harness against 399-0808 before ordering.
Part number reference for the 399-0808
This harness is one part sold under one number. Suppliers and parts books write it differently — you may see it as 399-0808, 3990808 · CA3990808. 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 Caterpillar 390F
It runs from the fuse box out to the front, rear and boom lights, exposed to weather and wash-down.
What it connects
- Switch and relay to the lamp groups — work lights, road lights and rear lamps.
- Lamp ground returns — the return path that fails first when a connector corrodes.
What a failing Caterpillar 390F harness looks like
| What the operator reports | Why the harness fits that symptom |
|---|---|
| One side of the machine dark | A branch or a ground point, not the lamps. |
| Lights flicker with vibration | A loose pin or a broken strand at a lamp pigtail. |
| Fuse blows when the lights are switched on | A short in the run, usually where it passes a panel edge. |
| Lights dim when another circuit loads up | Shared ground with too much resistance. |
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 Caterpillar 390F
Same type of harness on other machines
Product Description
Boom Headlight Wiring Harness for Caterpillar 390F excavator. OEM part number 399-0808. Direct replacement ensuring plug-and-play installation.
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 | 399-0808 |
|---|---|
| Compatible Model | Caterpillar 390F Excavator |
| Harness Type | Boom Headlight |
| Warranty | Packaging Machine Normal Use |
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