Product Overview

High‑quality used right rear tail light designed for Citroën C4 Coupe (3‑door). Ideal for professional workshops and DIY mechanics who search by OE numbers: 9646801677 and 6351T6. This unit is supplied without the bulb holder (socket) but includes the bulbs, making it a direct visual and functional replacement in most cases. The robust housing restores rear lighting functionality and vehicle appearance after damage or wear.

Key Features

• Direct Fit For Citroën C4 Coupe (3‑Door)
• Includes Bulbs; Socket Not Included
• OEM Reference Numbers: 9646801677 / 6351T6
• Suitable For Fast Replacement In Workshop Conditions

Technical Information

• Manufacturer: Citroën (Stellantis)
• Model: Citroën C4 (First Generation) Coupe 3‑Door
• Product Codes: 9646801677, 6351T6
• Additional Numbers: 6351T6 | 9646801677

Installation Recommendations

• Park The Vehicle Safely And Work On A Cold, Stable Surface.
• Access The Lamp From The Trunk: Remove Inner Trim Panels To Reach Mounting Screws Or Nuts.
• Unscrew Mounting Fasteners And Carefully Pull The Lamp Assembly Outwards To Avoid Breaking Mounting Tabs.
• Disconnect The Electrical Connector. Inspect Connector Pins For Corrosion Or Damage.
• Note: This Unit Is Supplied Without The Bulb Holder (Socket). Fit The Original Socket If Intact Or Replace With A Compatible Socket Before Installing If Required. Bulbs Are Included—Verify Bulb Types And Seating.
• Reinstall The Assembly, Tighten Fasteners To Manufacturer Torque Where Specified, And Check Alignment And Seal Integrity.
• Test All Light Functions (Brake, Tail, Indicator, Reverse If Applicable) Before Closing Trim Panels.

Why This Part Fails Most Often

Tail lights typically fail due to mechanical damage, water ingress, electrical contact corrosion, or aging components. Common causes include:

• Impact Damage From Minor Collisions Or Bumps Leading To Cracked Lens Or Broken Mounting Tabs.
• Moisture Ingress Causing Fogging, Short Circuits, Or Corroded Contacts.
• Vibration And Heat Cycles That Wear Bulb Filaments Or Damage Internal Wiring.
• Degraded Seals Or Gaskets Allowing Dirt And Water Into The Housing.

Maintenance Tips

• Inspect Tail Lights During Routine Service Intervals For Cracks, Condensation, And Secure Mounting.
• Replace Gaskets Or Seals When Replacing The Lamp To Prevent Future Moisture Problems.
• Use Dielectric Grease On Electrical Connectors To Reduce Corrosion Risk.
• Verify Bulb Types And Replace With Correct Wattage/Replacements To Avoid Overheating.

This replacement tail light is a practical and cost‑effective solution to restore rear lighting functionality and vehicle safety on Citroën C4 Coupe models. Search By OE Numbers 9646801677 And 6351T6 For Fast Identification.

This replacement rear lamp socket is designed for the right-hand tail light on Citroën C4 3-door Coupe models. It is an ideal part for professional workshops and independent mechanics performing lamp repairs or wiring fixes. The socket comes with part of the wiring harness and retains the bulb holders, which makes it a practical solution when the original connector is corroded, melted or the wiring insulation is damaged. Commonly searched by part numbers 9646801677 and 6351T6 — include these codes in your search to find the exact match quickly.

Technical Information

• Manufacturer: Stellantis / Citroën
• Model: Citroën C4 I Coupe (3-Door)
• Product Codes: 9646801677, 6351T6
• Additional Numbers: 6351T6 | 9646801677

How The Part Works And Why It Fails

The lamp socket holds and connects the rear bulbs to the vehicle wiring, ensuring power and a secure mechanical fit. Over time these sockets commonly fail due to corrosion from moisture ingress, heat damage from high-wattage bulbs or poor contacts causing increased resistance and local heating. Mechanical damage, cracked plastic or worn pins in the connector also lead to intermittent or complete loss of lighting function.

Replacement Frequency

There is no fixed service interval for a tail lamp socket. Failure usually occurs gradually and depends on environmental exposure, quality of previous repairs and the bulb type used. In practice, sockets may last many years but should be inspected if you experience flickering lights, intermittent operation or visible corrosion.

Installation Recommendation

Recommended For Experienced Mechanics And Competent DIYers. Typical Replacement Steps:

• Remove Interior Trim In The Boot/Trunk To Access The Tail Lamp Assembly.
• Unscrew And Withdraw The Lamp Cluster From The Body.
• Unplug The Wiring Harness Connector And Remove The Old Socket From The Lamp Housing.
• Fit The New Socket Into The Lamp Housing, Reconnect The Wiring And Secure Any Clips Or Seals.
• Test All Bulb Functions (Stop, Tail, Indicator, Reverse If Applicable) Before Reassembling Trim.

Always Disconnect The Battery If You Will Be Working On Live Circuits Or Cutting/Wiring The Harness To Avoid Short Circuits. Ensure Sealing Surfaces Are Clean And Use Dielectric Grease On Contacts If Needed To Reduce Future Corrosion.

Most Common Cause Of Failure

Corrosion And Heat Damage Are The Primary Causes. Water Entry Through Damaged Seals Or Cracked Lenses Leads To Oxidation Of Pins, While Repeated Thermal Cycling From Bulb Heat Causes Plastic Deformation And Contact Loss.

Part Numbers And Clear Identification Make Ordering Faster — Use 9646801677 Or 6351T6 When Searching. This Socket Is Supplied With A Section Of Wiring To Simplify Replacement And Reconnection.

High-quality replacement right rear tail light designed for Citroën C4 Coupé (3‑door). This unit comes complete with bulb holders and bulbs fitted, so it is ready for direct replacement in most repairs. Ideal for professional mechanics and competent DIYers who need a reliable, OEM-style lamp assembly. Common search references include part numbers 9646801677 and 6351T6 — include these in your search to find exact matches and speed up procurement.

Technical Information

• Manufacturer: Citroën (Stellantis)
• Model: Citroën C4 I Coupé 3‑Door
• Product Codes: 9646801677, 6351T6
• Other Numbers: 9646801677 | 6351T6

Fitment / Applications

Intended for Right Rear (Passenger Side) of Citroën C4 Coupé 3‑door (first generation). Verify visual match of mounting points and connector shape before installation — the product reference numbers above are commonly used to confirm fitment.

Function And Common Failures

The rear lamp assembly provides tail, brake, and indicator lighting as well as reversing light functions where applicable. Because this unit is supplied with bulb sockets and incandescent bulbs, the most frequent faults are simple bulb burnout and socket corrosion due to moisture ingress. Other common issues include cracked lenses from impacts, damaged mounting tabs, and corroded or loose electrical connectors. In accident damage cases the entire assembly is typically replaced rather than repaired.

Replacement Procedure

General replacement steps for a standard Citroën C4 Coupé rear lamp:

• Park vehicle on level ground and switch off ignition. For safety, remove the negative battery terminal if you will be working extensively on the electrical connectors.
• Access the lamp from inside the boot/trunk by removing the trim panel covering the lamp mounting area.
• Unscrew the lamp retaining nuts or bolts (usually accessible from inside the boot) and carefully pull the lamp assembly away from the body.
• Disconnect the wiring harness by releasing the connector clip. If the unit is fitted with bulb holders, twist out the bulb holders to remove bulbs.
• Fit the new lamp: reconnect the wiring harness, insert bulb holders, align the assembly and tighten the retaining fasteners evenly. Refit the interior trim.
• Test all lamp functions (tail, brake, indicator, reversing) before returning the vehicle to service.

Installation Recommendations

• Use anti‑seize or threadlocker on fasteners as appropriate to prevent future seizure or loosening, but follow manufacturer torque specs if available.
• Check and, if necessary, clean the connector contacts and apply dielectric grease to prevent future corrosion.
• Replace bulbs with the correct type and rating specified for the vehicle. Incorrect bulbs can lead to poor light output or electrical issues.
• After installation, verify correct operation of all lighting circuits and check for any dashboard warnings related to lighting.

Why This Part Typically Fails

Failures are most commonly caused by burned‑out bulbs and moisture ingress that corrodes sockets and connectors. Impact damage from minor collisions can crack the lens or break mounting tabs. Over time, vibration and thermal cycling can degrade seals and allow water in, accelerating corrosion and electrical faults.

Notes For Professionals

Part numbers 9646801677 and 6351T6 are frequently used identifiers — include them in parts searches or repair orders to ensure correct supply. This lamp is supplied with bulb holders and bulbs, reducing installation time compared with a bare housing.