FAQ
TL;DR: 14 E‑codes map approval countries; "the left/right arrow always points to the outer contour." E4 means Netherlands approval, not traffic side. This FAQ helps DIYers and buyers verify RHT/LHT compatibility, decode arrows, and avoid fails. [Elektroda, Millaka, post #18041070]
Why it matters: Picking the wrong traffic-side lamp causes glare, test failures, and wasted money.
Quick Facts
- E4 identifies the Netherlands as the approval country under ECE; it’s not a performance grade. [Elektroda, Millaka, post #18041070]
- The lens arrow points toward the vehicle’s outer edge; it marks left/right installation side. [Elektroda, Millaka, post #18041070]
- H4 halogen bulbs have three lugs; a vertical top lug aligns for right‑hand traffic cutoff. [Elektroda, sanfran, post #18040662]
- UK inspections accept tape masking of the kick‑up on foreign lamps when aligned. [Elektroda, sanfran, post #18043532]
- Some two‑wheelers use symmetrical “BS” lenses, making traffic side irrelevant. [Elektroda, BANANvanDYK, post #18044110]
What does the E4 mark on my headlamp actually mean?
E4 indicates the lamp was type‑approved in the Netherlands. E‑codes map to approval countries (e.g., E1 Germany, E11 UK). It does not denote beam direction by itself. [Elektroda, Millaka, post #18041070]
Does the E‑marking tell me if a lamp suits right‑ or left‑hand traffic?
No. The E‑mark shows where the product was approved, not the intended traffic side. Traffic direction depends on optics and beam pattern. “It was approved there.” [Elektroda, dizba, post #18040915]
What does the arrow on the lens indicate?
It points toward the car’s outer contour and identifies the installation side (left/right). Expert quote: “the left/right arrow always points to the outer contour of the vehicle.” It is not the traffic‑side indicator. [Elektroda, Millaka, post #18041070]
Is a right‑pointing arrow a UK (left‑hand traffic) headlamp?
No. That arrow marks the left or right position on the vehicle, not UK vs. continental use. Confirm traffic side by the beam shape on a wall. [Elektroda, BANANvanDYK, post #18041032]
How can I test RHT vs LHT at home with an H4 bulb?
Install the H4 bulb and power the lamp facing a wall. The cutoff should rise to the right for right‑hand traffic. It rises to the left for left‑hand traffic. This quick test is decisive. [Elektroda, sanfran, post #18040662]
How do H4 lug positions differ between RHT and LHT lamps?
H4 bulbs have three lugs. For right‑hand traffic optics, the top lug sits perfectly vertical. Left‑hand traffic units rotate the bulb slightly clockwise when viewed from the mounting side. [Elektroda, sanfran, post #18040662]
Can I determine compatibility 100% from markings alone?
Yes, but only if the lamp explicitly shows RHD/LHD on the label. Without that, verify the beam pattern or consult the model catalog. [Elektroda, BANANvanDYK, post #18041032]
Can I adapt a left‑hand‑traffic lamp for right‑hand traffic without buying new?
Yes, by re‑indexing the H4 bulb to correct the cutoff. One rider filed the notches, set the upper tab vertical, and passed inspections.
- Slightly enlarge H4 locating notches.
- Rotate bulb so the top tab is vertical.
- Test on a wall and aim correctly. [Elektroda, Trabi, post #18043233]
Will masking tape pass a UK inspection with continental headlights?
Yes. In the UK, masking the kick‑up area with tape is accepted during inspection when the beam is correctly aligned. [Elektroda, sanfran, post #18043532]
What does “BS” on a motorcycle lens mean for traffic side?
It denotes a symmetrical beam unit. With BS‑marked lenses, the traffic side is irrelevant; HS1/H4 or S2 can be used accordingly. [Elektroda, BANANvanDYK, post #18044110]
I see “RHD” on a sticker. What does that confirm?
It confirms the lamp is for right‑hand‑drive vehicles on left‑hand traffic roads, like the UK. That marking is decisive. [Elektroda, BANANvanDYK, post #18041032]
What does E20 mean on Polish lights?
E20 indicates Poland as the approval country. You will see E20 on Polish‑approved lighting such as beacons. [Elektroda, pepe150, post #18041187]
What happens at inspection if the cutoff steps the wrong way?
Expect an immediate fail. Inspectors spot a beam that kicks up on the wrong side instantly and advise correction or replacement. [Elektroda, Trabi, post #18043233]
Why do some cars use 25W xenon, and does that affect washers?
25W xenon reduces luminous flux to avoid headlamp washer requirements. It’s a design choice seen in newer vehicle lighting. [Elektroda, BANANvanDYK, post #18044110]
How can I verify a DEPO 2701685 lamp’s traffic side?
Look for an RHD/LHD sticker first. If absent, install an H4 bulb and check the cutoff direction on a wall. The beam tells you. [Elektroda, BANANvanDYK, post #18041032]
