Caterpillar 336E Fuel Injector Wiring Harness
Fuel Injector Wiring Harness for Caterpillar 336E excavator. OEM part 637-2653. Direct replacement.
Fitment
Fits the Caterpillar 336E Excavator. ECS lists 7 harness sections for this machine — see all 7 sections for the Caterpillar 336E before you order, because the sections are not interchangeable.
Part number reference for the 637-2653
This harness is one part sold under one number. Suppliers and parts books write it differently — you may see it as 637-2653, 6372653 · CA6372653. 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 336E
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 Caterpillar 336E harness looks like
| What the operator reports | Why the harness fits that symptom |
|---|---|
| One cylinder cold or dead | A cut injector circuit reads as a mechanical injector failure until the circuit is measured. |
| White or grey smoke at idle | Unburnt fuel from a cylinder that is not firing correctly. |
| Rough idle that smooths with rpm | Typical of one intermittent injector circuit. |
| Open-circuit or short-to-ground code for one injector | Check the run to that cylinder before replacing the injector. |
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 336E
Same type of harness on other machines
Product Description
Fuel Injector Wiring Harness for Caterpillar 336E excavator. OEM part number 637-2653. 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 | 637-2653 |
|---|---|
| Compatible Model | Caterpillar 336E Excavator |
| Harness Type | Fuel Injector |
| 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