Rear View Mirror Auto Dim Top Sensor Land Rover Discovery 4 Range Rover Sport

#72

♻️ GENUINE LAND ROVER DISCOVERY 4 L319 AUTO-DIMMING INTERIOR REAR VIEW MIRROR – AH42-17E678-AC / LR019913

Genuine used Land Rover Discovery 4 L319 interior rear-view mirror with automatic dimming / auto-dip function.

The electrochromic mirror automatically reduces reflected glare from headlights behind the vehicle when driving at night, improving rear visibility and driver comfort.

Engineering Part Number: AH42-17E678-AC

Alternative Number: AH4217E678AC

OE / Cross Reference: LR019913

Part Type: Interior Rear View Mirror

Function: Automatic Dimming / Auto Dip

Position: Front Centre Interior / Windscreen

System: Interior Visibility / Auto-Dimming Mirror System

Manufacturer: Land Rover / OEM

Condition: Genuine Used

Compatibility

Confirmed application:

• Land Rover Discovery 4 L319

• Discovery 4 models equipped with the matching electrically operated auto-dimming interior mirror

• 2.7 TDV6 applications where matching equipment is fitted

• 3.0 TDV6 / SDV6 applications where matching equipment is fitted

The exact AH42-17E678-AC engineering number is specifically catalogued as a Discovery 4 L319 Interior Rear View Mirror Auto Dip, with LR019913 given as a substitute/OE reference. (GlobalParts)

Related Land Rover Applications

Similar 17E678 mirrors were used across other Land Rover and Range Rover models, including:

• Range Rover Sport L320

• Freelander 2 / L538 applications with certain mirror versions

• Later Range Rover Sport applications using different CPLA/GPLA 17E678 variants

However, AH42-17E678-AC should not automatically be advertised as fitting every Range Rover Sport.

For example, later L494 Range Rover Sport vehicles are documented with different engineering numbers such as CPLA-17E678-AA and GPLA-17E678-GC, particularly where additional driver-assistance equipment is fitted. (RRSport)

Technical Information

This mirror uses electrochromic automatic-dimming technology.

When bright headlights from a following vehicle are detected, the mirror darkens automatically to reduce reflected glare.

When the glare decreases, the mirror returns towards its normal reflective state.

This provides:

• Reduced glare from vehicles behind

• Improved comfort during night driving

• Less need for manual mirror adjustment

• Factory Land Rover interior appearance

• Automatic response to changing lighting conditions

Auto-Dimming System Information

The mirror incorporates light-sensing technology used to determine when dimming is required.

The system relies on the correct:

• Mirror electronics

• Light sensing elements

• Electrical power supply

• Wiring and connector

• Vehicle specification

For correct operation, the sensor areas should not be obstructed.

Common Symptoms / Reasons for Replacement

• Mirror no longer automatically dims

• Mirror remains permanently dark

• Intermittent auto-dimming operation

• Mirror glass damaged

• Internal electrochromic layer deteriorated

• Mirror housing damaged

• Electrical connector damaged

• Mounting point damaged

• Sensor fault

• Replacement required following windscreen work

• Original mirror missing

Important Diagnostic Information

A non-functioning auto-dimming mirror does not automatically mean the complete mirror is faulty.

Before replacement, check:

• Electrical connector

• Wiring

• Power and ground supply

• Sensor areas for obstruction

• Mirror mounting

• Vehicle specification

If replacing with a used unit, matching the complete engineering number is strongly recommended.

Installation

The mirror mounts to the factory interior windscreen mounting arrangement.

During installation:

• Compare the mounting bracket with your original

• Disconnect/connect the electrical plug carefully

• Avoid damaging the windscreen mounting point

• Ensure wiring is correctly routed

• Do not obstruct the light sensors

Extra care should be taken when removing a mirror from the windscreen mounting point to avoid damaging the windscreen.

Programming / Coding

For a straightforward like-for-like AH42-17E678-AC replacement, separate programming is not normally expected for the basic auto-dimming function.

However, mirrors with additional equipment can have different electrical and vehicle configuration requirements.

This is particularly important when comparing the Discovery 4 mirror with later Range Rover Sport mirrors incorporating features such as Auto High Beam Assist or driver-assistance cameras. (RRSport)

Important Compatibility Note

⚠️ Please match the complete mirror specification before purchasing.

Check:

• AH42-17E678-AC

• AH4217E678AC

• LR019913 where applicable

• Electrical connector

• Number of pins

• Windscreen mounting arrangement

• Sensor configuration

• Mirror housing shape

• Additional driver-assistance equipment

• Listing photographs

Land Rover used numerous 17E678 mirror variants depending on model, year and vehicle equipment.

Do not assume that another 17E678 mirror is interchangeable simply because the base engineering number is similar.

Condition

Genuine used Land Rover part.

May show normal signs of previous use, including light scratches, marks or cosmetic wear to the housing.

Please inspect all listing photographs carefully for the condition of the mirror glass, housing, connector and mounting point.

♻️ Genuine Land Rover Discovery 4 L319 electrochromic auto-dimming interior rear-view mirror AH42-17E678-AC / LR019913 – ideal replacement for a damaged or faulty original auto-dip mirror.