Left vs Right Car Parts: How to Avoid Ordering the Wrong Side

Searching for a ‘BMW side mirror’ online can return many listings, and side labels are not always explained clearly.

Because there’s no clear clarification of ‘left’ vs ‘right’ car parts on a listing.

‘Right’ may refer to the vehicle’s right side when seated in the driver’s seat facing forward, or it may be used from another viewing perspective. The exact convention should be confirmed.

Then there is the potentially confusing terminology of ‘driver side’ and ‘passenger side.’ These references change depending on whether the vehicle is right-hand drive or left-hand drive.

This guide explains how to interpret side labels, check OE references and confirm the correct part before ordering.

TL;DR

• Left and right usually mean from the driver’s seat facing forward, but always confirm the catalogue’s convention.

• Part side and LHD or RHD compatibility are separate checks, so both must match the vehicle.

• A matching part number does not guarantee fitment unless it is verified against the exact vehicle.

• Control arms, suspension links and brackets may differ between left and right because of their design or mounting.

• Body panels, brackets and mounts can vary by side, drive layout, trim level or production period.

Why ‘Left’ and ‘Right’ on a Part Listing Isn't as Obvious as It Sounds

There are several conventions for naming LH vs RH car parts.  Some label parts as ‘driver side/passenger side’. Others simply write ‘right’ and ‘left.’ 

The problem is that some listings do not specify the viewing perspective. The apparent side can change depending on whether you view the vehicle from inside or outside. But the riskiest term is ‘driver’s side’ as it changes with right-hand drive or left-hand drive. 

To reduce confusion, AtoZ Auto Parts’ listings may specify OE numbers alongside left and right labels for mirrored components. For example a Mercedes upper control arm is listed as ‘Left 1663301707’ and ‘Right 1663301807’ instead of a vague driver side vs passenger side part.

The Two Safe Conventions (and Why ‘Driver/Passenger Side’ isn't One of Them)

When a listing uses ‘left’ or ‘right,’ it may follow one of these common conventions:

Convention 1: Driver-seated perspective

Imagine sitting in the driver’s seat and facing forward. Your left is the vehicle’s left side, and your right is the vehicle’s right side. This is a widely used convention in many parts catalogues, including AtoZ Auto Parts listings, but it should still be confirmed. 

Convention 2: Front-facing perspective

Some listings define left and right as if you are standing in front of the vehicle and looking at it. In this view, the vehicle’s left and right appear reversed compared with the driver-seated perspective.

Other than these two, a listing mentioning driver side vs passenger side parts can be confusing. 

This is because the meaning depends on which side the steering wheel is on in that vehicle’s configuration. This can be difficult to interpret for Indian buyers, especially when ordering imported parts. Instead of assuming the meaning, confirm the physical side with the supplier.

Parts Where Getting the Side Wrong is Most Costly

It gets more riskier with some parts if you order the wrong side. For these parts, ‘left’ and ‘right’ affect more than geometry. They can also affect mounting design, electrical connections, beam pattern or safety-related functions.

Headlights

Headlights have a deeper issue than just identifying left vs right sides. The low-beam pattern is asymmetrical. It is designed to illuminate the driver’s own side of the road more effectively while limiting glare towards oncoming traffic.

Headlight beams are asymmetrically cut so that the light doesn't dazzle oncoming drivers. The beam pattern depends on whether the headlamp is designed for left-hand traffic or right-hand traffic. In a left-hand-traffic market such as India, the low beam is generally designed to provide more illumination along the left side of the road while limiting upward light towards oncoming traffic on the right. 

Confirm whether the headlamp is designed for the correct traffic direction and vehicle specification, not merely the correct physical side. This can be done through correctly matching the OE number. 

For example, the Land Rover headlight bracket listing at the AtoZ Auto Parts’ website shows separate left (LR187208) and right (LR167168) part numbers.

Mirrors

The two side mirrors aren’t interchangeable. The housing shape, glass curvature, mounting points and, where fitted, motor and actuator wiring can differ between sides.

Mounting points and left-right mirror orientation can also differ between sides, depending on the vehicle design.

Mirror design depends on both the vehicle’s physical side and the driver’s position. A mirror listed as ‘right’ may be the driver-side mirror on a right-hand-drive vehicle, but it remains the vehicle’s right-side mirror. 

For example, on a right-hand-drive vehicle, the right-side mirror is typically the driver-side mirror. On a left-hand-drive vehicle, the right-side mirror is typically the passenger-side mirror.

This distinction matters, so confirm whether the part is intended for a left-hand-drive or right-hand-drive vehicle. And that’s why, AtoZ Auto Parts’ mirror listings clearly separates right mirrors from left mirrors with OE numbers. 

Control Arms and Suspension Links

Their curve, angle, and mounting points, all are designed to fit the parts around it. Their shape, angle and mounting points are designed to align with the surrounding suspension and chassis components.

Manufacturers usually give them OE part numbers for left and right sides with one different digit to clarify the distinction. AtoZ Auto Parts’ Mercedes upper control arm pair (Left 1663301707, Right 1663301807) and similar front-lower control arm sets differ by only a digit or two between sides. 

Do not assume that a near match number is a safe substitute for the exact one. 

Body Panels and Brackets

Many body panels are mirrored to fit the left and right sides of the vehicle. Their mounting points, clips and attachment features may differ between sides.

A bracket built for the opposite corner won't line up with that corner's mounting points. This can result in misaligned panels or poor fitment. 

For example, Audi Q3 headlamp brackets may use separate left and right references, such as 8U0805607A and 8U0805608A. A bracket intended for the opposite side may not align with the adjacent mounting points.

How to Read a Listing's Side Convention Before Ordering

As different auto stores operate with different conventions, it becomes hard to know what ‘right’ or ‘left’ means in a listing. Here are some things you can do to confirm:

• Look for a listing that states its convention clearly rather than assuming. For example, ‘LH means left as seated in the vehicle.’

• Cross-check the OE part number left vs right where one is given. Paired left and right parts may have similar OE references, but the difference can involve one digit, several digits or a suffix.

• Where a listing uses ‘driver side’ or ‘passenger side’ wording, confirm what physical side that means for the specific vehicle before relying on it.

(To know how to find and match OE numbers, refer to AtoZ Auto Parts’ OE part number matching guide)

A Quick Way to Confirm Which Side You Actually Need

Wondering how to know which side car part you need? These tips can help you save the guesswork: 

• Sit in the driver's seat facing forward and use that as a reference point for ‘left’ and ‘right.’ This matches the convention used in many parts catalogues, including AtoZ Auto Parts’ LH/RH listings.

• Photograph the existing part and its mounting location. Then, compare it directly against the listing photo rather than relying on a side label alone. 

• If you’re still not sure, send the seller the OE number or a photo. 

Fitment Checklist to make sure you buy the right side part

• Confirm which side convention the listing uses for differentiating left vs right car parts instead of assuming.
  

• ‘Driver side’ and ‘passenger side’ are not universally standard references. They can mean different sides depending on the country. Confirm the meaning for the specific vehicle you are ordering the part for.

• Cross-check the OE part number rather than relying on a text side label alone, especially for mirrors, headlights, control arms and body panels/brackets.

• For headlights specifically, driving configuration matters more than just LH vs RH car parts. Confirm that the part is built for the correct traffic side and not only the correct physical mounting side.

• Compare a photo of the existing part against the listing photo before ordering.

• Ask the seller for confirmation when a listing is vague or unclear.

Frequently Asked Questions

1. What do ‘LH’ and ‘RH’ mean on a parts listing? 

It means left hand and right hand which is almost always defined as if seated in the vehicle facing forward. But it’s better to confirm LH vs RH car parts, since it is not universal.

2. Is ‘driver side’ always the left side? 

No. It depends on which side the steering wheel is on for that vehicle's configuration. On a right hand drive vehicle the driver side is the right side, the opposite of a left hand drive vehicle.

3. Can I tell the correct side just from a listing photo? 

Not reliably for mirrored parts like control arms, mirrors or brackets. Cross-check the OE number or compare against the existing part, since OE part numbers left vs right are often only a digit or two apart.

4. Does a headlight's side matter beyond which one it bolts to? 

Yes, it matters because of the beam pattern. The low beam cutoff is aimed differently depending on which side of the road the vehicle is built to be driven on.