Overview

This battery charge state unit monitors and reports the condition and state of charge of the vehicle battery, helping the charging system and onboard electronics manage charging, start‑stop functions and battery diagnostics. It is designed for a range of Stellantis Citroën and Peugeot models and is commonly searched by part numbers listed below, which makes it easy for professional technicians and experienced DIYers to find the correct replacement.

Applications

Typical fitment includes (but is not limited to): Citroën C4 II, Citroën C4 Picasso / C4 Picasso II, Peugeot 3008 I, Peugeot 308, Peugeot 5008 I. Before installation verify physical fitment and connector type against the original part.

Technical Information

• Manufacturer: Stellantis (Citroën / Peugeot)
• Model: Battery Charge State Unit
• Product Codes: 9676592080, 9802043480, 6500KT
• Other Numbers: 6500KT | 9676592080 | 9802043480

Function And Symptoms

The module continuously measures battery voltage (and, depending on vehicle, current and temperature) and transmits battery state data to the vehicle network. When the unit fails, common symptoms include persistent battery warning lamp, incorrect battery charge indication, reduced charging efficiency, erratic start‑stop behavior or warning messages related to the charging system and battery health.

Why The Part Typically Fails

Failures are usually caused by environmental and electrical stresses: long‑term exposure to moisture and road salt, corrosion at connector pins, thermal cycling in the engine bay, vibration fatigue and electrical surges from a failing alternator or jump starts. In some cases repeated deep discharges or improper battery replacement (wrong battery chemistry or capacity) accelerate module failure.

Installation Recommendations

• Always disconnect the negative battery terminal before starting work to avoid short circuits and protect vehicle electronics.
• Locate the module (commonly mounted near the battery or in the engine bay electrical cluster), note connector orientation and secure mounting points before removal.
• Label or photograph connectors if necessary, then unplug harnesses and remove fasteners. Fit the replacement unit in the reverse order and ensure all connectors seat fully and locking tabs engage.
• After mechanical installation, verify charging system operation and battery parameters with a diagnostic tool. Some vehicles may require an adaptation or coding procedure to register the new unit or update battery profile parameters; use PSA diagnostic software where applicable.
• Check and clean battery terminals and earth points while the battery is reconnected to reduce the chance of future faults.

Practical Tips For Professionals

When replacing the module, inspect the battery condition and alternator output. A marginal or faulty battery can mask as module failure; replace the battery if capacity is low. Protect new modules from moisture and secure wiring to minimize vibration. Use dielectric grease on connector pins when corrosion risk is present.

This battery negative/ground engine harness is an OE‑style replacement designed for Citroën and Peugeot applications. It secures the negative pole of the battery to the engine block and chassis ground, ensuring reliable return paths for starter, alternator and vehicle electronics. Supplied under part numbers 9676811780 / 9802871580 / 5638PN, this harness is commonly used on smaller petrol and diesel engines and is a direct-fit option where the original cable assembly has failed, corroded or been damaged by heat and mechanical wear.

Key Benefits

• Direct replacement for OE harnesses with matching routing and connector interfaces.
• Restores Good Grounding And Electrical Stability For Starting And Charging Systems.
• Compatible With Vehicles Equipped With 1.4 16V, 1.4 HDi And 1.4 VTi Engine Variants (See Compatibility).
• Allows Optional Fitment Of Battery Charge State Unit (6500KT) If Required.

Function

The harness provides the main negative connection between the battery, engine block and vehicle chassis. A solid, low‑resistance ground is essential for starter motor performance, alternator charging regulation and stable operation of all onboard electronics. The assembly typically includes lug terminals, insulated cable sections and attachment points designed to match factory routing.

Compatibility / Typical Applications

Fits Various Citroën And Peugeot Models Including, But Not Limited To, Citroën C4 II And Other Small‑Platform Vehicles Equipped With 1.4‑L Engines (1.4 16V, 1.4 HDi, 1.4 VTi). Searchable By OE Numbers: 9676811780, 9802871580, 5638PN.

Technical Information

• Manufacturer: Stellantis / Citroën / Peugeot
• Model: Compatible With Multiple Citroën And Peugeot Models (See Compatibility Section)
• Product Codes: 9676811780, 9802871580, 5638PN
• Additional Numbers: 6500KT (Battery Charge State Unit – Sold Separately)

Installation Recommendations

• Always Disconnect The Battery Before Starting Work To Avoid Short Circuits And Damage.
• Follow Factory Routing And Secure All Clips And Fasteners To Prevent Chafing And Heat Exposure.
• Clean The Grounding Points To Bare Metal Before Reattaching The Lug; Ensure Good Mechanical Contact.
• Tighten Terminals According To Manufacturer Specifications And Protect Exposed Connections From Corrosion.
• If The Vehicle Uses A Battery Charge State Unit, Install The Unit (6500KT) Where Applicable And Ensure Connectors Are Correctly Seated.
• After Installation, Check Starter Crank Behavior And Charging Voltage To Confirm Proper Operation.

Why The Part Fails

Most Failures Are Caused By Corrosion At Terminals, Mechanical Damage Or Heat Exposure. Road Salt, Moisture And Battery Acid Can Accelerate Deterioration Of The Cable Ends And Lugs. Repeated Current Loads And Vibration May Cause Fractures Or Loss Of Contact, Leading To Hard Starts, Intermittent Electrical Faults Or Irregular Charging.

Signs You Need Replacement

• Difficult Engine Cranking Or Slow Starter Response.
• Intermittent Electrical Faults, Flickering Lights Or Erratic Sensors.
• Visible Corrosion, Melted Insulation Or Loose Terminals On The Negative Pole.
• Voltage Drop Under Load When Tested With Multimeter.

Fitment Notes

Part Numbers Are Common Search Terms For Mechanics And DIY Enthusiasts: 9676811780, 9802871580, 5638PN. Verify Physical Match With The Existing Harness (Connector Shapes, Lengths And Attachment Points) Before Final Installation. Do Not Use If Any Connector Or Insulation Appears Compromised.

Warranty And Quality

This Harness Is Supplied As A Replacement Component Intended To Restore Proper Grounding And Electrical Function. It Is Manufactured To Fit Factory Specifications For The Listed Part Numbers. For Long‑Term Reliability, Ensure Proper Installation And Protection Against Corrosion.