The Headlight Bulb Sourcing Checklist: H7, 9005 vs 9006, H13, and H4 LED Supplier Traps

Who this checklist is for

This is for B2B buyers sourcing headlight bulbs — H7, 9005, 9006, H4, H11, H13, the full range — for wholesale, distribution, repair shops, or fleet supply. If you're ordering bulbs by the hundred, this applies.

You don't need to be a lighting engineer. You need to avoid shipping the wrong bulb to 400 accounts and eating the return freight.

I've been handling parts sourcing orders since 2017. That's about nine years now — or eight, depending on how you count the first year. Made plenty of mistakes. This checklist is the scar tissue talking.

Six steps below. That's it.

Step 1: Match the bulb code to the housing, not the vehicle model

The first mistake almost every new buyer makes: looking up a bulb by the vehicle model. "This fits a 2018 Silverado, so..." No.

A single vehicle model year can ship with two or three different headlight configurations. Bulb codes belong to the housing. You need the housing part number or the bulb code stamped on the original socket.

On a 900-piece mixed order back in 2019, we assumed every base-model trim used the same bulb. Wrong. About 30% of the units needed a different code. That's 270 bulbs that went straight back to the shelf. Cost: roughly $2,400 in labor and repackaging. Not ideal, but workable — we didn't lose the customer. But I learned the lesson.

Step 2: Know the 9005 vs 9006 headlight bulb difference cold

This one comes up a lot. The 9005 headlight bulb (HB3) and the 9006 (HB4) look similar on a screen. In the hand, they're different.

The 9005 has a straight, narrower base. The 9006 has a wider base with a small offset tab. They will not seat correctly in the wrong socket. If you force it, the bulb sits crooked, the beam pattern is off, and the customer is unhappy six weeks later.

Why it matters for sourcing: some suppliers will list both under "9005/9006 compatible." That's a red flag. It usually means they're either selling a low-quality universal base or they don't know their own catalog. Either way, verify before you buy.

We caught this once on a 50-piece sample batch. The "9005" bulbs we received had base dimensions within tolerance, but the connector tab was 1.2mm off. Enough to fit a 9006 housing, not a 9005. We rejected the lot. Bottom line — if the spec sheet doesn't explicitly call out the base type, ask.

Step 3: Verify H7 and H13 fitment against actual stock

An H7 headlight bulb is a single-filament bulb with a specific retaining ring size. An H13 headlight bulb is dual-filament with a different base entirely. They're both common. They're both easy to mix up in a warehouse when SKUs are printed in small text.

The fix: don't trust the label. Trust the calipers and the bulb type chart.

I built a "fitment reference sheet" for our top 20 bulb codes — H7, H13, H11, 9005, 9006, H4, D2S, D3S. Each entry has the base type, retaining ring diameter, connector shape, and a line drawing. Took about four hours to put together. Saved us from at least six wrong picks in the last 18 months.

One more thing on H7: if you're sourcing for European vehicles, some housings are pickier about overall bulb length than the spec sheet suggests. This worked for us on domestic and Japanese makes, but our situation was mostly North American distribution — your mileage may vary if you're deep in EU-specific fits.

Step 4: Screen H4 LED headlight bulb suppliers on specs, not sticker price

Car H4 LED headlight bulbs are the wild west of the category. There are hundreds of suppliers. Maybe a dozen are worth a repeat order.

When I'm vetting car H4 LED headlight bulb suppliers, I ignore the per-unit price for the first round. Instead, I ask for:

• Lumen output — and whether it's measured or "estimated"
• Color temperature in Kelvin, with a tolerance range
• Power draw in watts, per bulb
• Base type specification (P43t for H4, typically)
• Any test reports they can share

If a supplier can't send a one-page spec sheet within two business days, that tells me something about after-sales support too. Probably not a deal-breaker on its own, but it's a data point.

I once ordered 200 H4 LED units based on price alone. The "estimated 8,000 lumens" came in closer to 4,200 on our bench test. Not a disaster — they worked, they just weren't what was promised. We sold them at a smaller margin and moved on. Lesson learned the hard way: estimated is a word that should make you ask more questions.

Step 5: Run the size chart against real order history

A bulb size chart is only useful if it matches what you actually stock. Sounds obvious. It isn't.

Here's the step most buyers skip: pull your last 90 days of order data and cross-reference every bulb code against the supplier's size chart. I've found mismatches on three separate occasions — usually in the H7 and H13 ranges where the chart lists a "universal" note that doesn't apply to certain housings.

That check takes maybe 40 minutes. Catching one wrong code on a 300-piece order saves way more than that in headaches.

Step 6: Do a pre-order audit on the whole cart

Before the purchase order goes out, I run a six-line audit. Every time. No exceptions.

1. Bulb code check: Does every line item match a verified code from the fitment sheet?
2. Quantity check: Does the quantity match the forecast, not the last order?
3. Spec check: Are lumens, Kelvin, and wattage explicitly confirmed in writing?
4. Supplier check: Is this a repeat supplier with a documented track record, or a new one?
5. Price check: Is the quote within the ballpark of the last three quotes for the same spec?
6. Lead time check: Does the promised ship date leave a buffer for customs or freight delays?

This checklist has caught 47 potential errors in the past 18 months — wrong codes, missing specs, quantity typos. Around eight of those would have been serious enough to trigger a return or a customer complaint. Do the math on what that would have cost.

Common mistakes to avoid

A few things that don't fit neatly into a step but will bite you anyway.

Assuming "standard" means the same thing. Every supplier has a slightly different definition of standard packaging, standard lumen tolerance, standard whatever. Ask for the actual numbers. What I mean is: make them put it in writing.

Skipping the sample. On any new supplier, order a small batch first. We do 20-50 units. It costs a little more per unit. It saves a lot more in returns.

Trusting the photo. Product photos are optimized. Bench-test the sample with a real housing before committing to a full run.

Forgetting about the certification question. If your market requires DOT, SAE, or ECE compliance, get the documentation in writing before ordering. Don't assume — verify at the official source and get the supplier's paperwork on file.

The bottom line: sourcing headlight bulbs isn't complicated. It's just detail-heavy. The buyers who get it right aren't smarter — they just have a checklist and actually use it.

Bulbspan Sourcing runs this process on every bulb order, for the same reason. It works.