Who Changes Headlight Bulbs? A Maintenance Buyer's Checklist for Champion Spark Plugs, Shock Struts, and Sensors

I'm not a mechanic. I'm the office administrator who handles purchasing for a 40-person company with five fleet vehicles and two buildings. I manage roughly $45,000 a year in maintenance orders across a mechanic's shop, an HVAC contractor, and my parts suppliers. This checklist is the one I wish I had when I took over purchasing in 2021.

Use it when a maintenance request lands on your desk and you need to know three things: which part, which labor, and which trigger. It covers common replacement parts from Champion spark plugs to shock strut assemblies, and it works for vehicles and building equipment. There are six steps, plus a few mistakes I've made myself.

1. Start with the part number, not the part name

Champion spark plug could mean a dozen different plugs. Champion spark plug RC12YC is a specific part. Champion CJ8 spark plug is another specific part, usually in our small-engine inventory. The names look close. The parts don't work the same way.

Before you order anything, find the part number from at least two sources: the old part if it's still in hand, the owner's manual, or the manufacturer's cross-reference. If two sources disagree, call the supplier and ask. Don't rely on an online listing photo. What most people don't realize is that photos are sometimes generic across part numbers.

2. Classify the job: scheduled, condition-based, or calibration-based

Replacement parts fall into three buckets.

• Scheduled – spark plugs, filters, gaskets. You replace them because the interval says so, not because they look bad.
• Condition-based – shock struts, belts, hoses. You replace them when they leak, sag, crack, or otherwise stop doing their job.
• Calibration-based – sensors and transmitters, like a pressure differential transmitter. You replace or recalibrate when the reading drifts outside a known range.

Shock strut replacement is a condition-based job. If one is leaking or the vehicle bottoms out over a speed bump, don't schedule it for next month. It affects steering and tire wear. I learned this after a rear strut left a small puddle on the parking lot and the shop bill doubled because we needed two new tires.

The pressure differential transmitter doesn't work like a wear part. It doesn't warn you when it starts to fail. It just gives a reading that slowly stops making sense. That's why it belongs in the third bucket.

3. Decide who actually does the work

This is the who changes headlight bulbs? question. The answer isn't always obvious.

Can a general maintenance person handle it? Maybe. Should they? Depends. For a typical fleet sedan, changing a headlight bulb is a 15-minute job for a general maintenance person. For some SUVs, you need to remove the battery tray or the front fascia. In that case, the job goes to a shop, and the labor quote matters more than the bulb price.

If it's a halogen bulb, don't touch the glass. Skin oil creates a hot spot, and the bulb can crack. That's the kind of detail that separates a quick fix from an afternoon pain.

The same applies to a pressure differential transmitter. It doesn't require a full HVAC contractor if the system is straightforward, but it does require someone who can verify the pressure range and calibrate it. Maintenance person with a screwdriver is not the same as person with a manometer.

Rule I use: if the labor requires lifting a vehicle, opening a refrigerant line, or removing body panels, it's not a hand-it-to-anyone task.

4. Ask what the replacement interval is really tied to

Here's something many buyers skip. They install a new part and don't write down the mileage or date. Then, the next time the same problem appears, nobody knows whether it's normal or early.

When we replaced the Champion spark plug RC12YC in a fleet engine, I recorded the date and mileage on the work order. When the same vehicle came back with a misfire two years later, we knew whether the plug was due. Without that note, we'd be guessing.

For shock strut replacement, record the mileage at installation. The next inspection can check whether the part has been in service for 20,000 or 60,000 miles. That changes the repair decision.

For a pressure differential transmitter, the reading after installation becomes the new baseline. If you don't record it, future testing has no reference point.

Also, don't forget the severe service schedule in the owner's manual. Short trips, cold starts, dusty sites, and stop-and-go routes all shorten intervals. Our vehicles do short trips, so I don't wait until the exact miles in the basic chart.

5. Confirm the part when it arrives

I once said we need a Champion CJ8 spark plug. The driver heard we need a Champion spark plug. The box on the dock had a different number. It looked right. It wasn't. The tech caught it before installation, but only because I had written the part number on the work order.

Now I check every box against the purchase order before it goes into the parts drawer. This sounds obvious, but it's easy to skip when you're processing 60-80 orders a year. Better to spend 30 seconds checking than to pay for a second labor charge.

If you're ordering a shock strut replacement, check whether the unit is loaded or bare. A loaded strut comes with the spring already installed. A bare strut requires swapping the spring over. They are not the same part, and the photos on supplier sites don't always spell this out.

6. Get a photo of the old part before it's thrown away

This is the step that feels unnecessary until you need it. When the old part comes off, ask the technician to take a photo with the old part number visible. That photo helps with warranty claims, return cores, and future reference.

For a shock strut, the photo also confirms which position it came from. Left and right struts are often different parts. A photo prevents a wait, is this the left side? problem after the old parts are in the scrap bin.

Notes and common mistakes

1. Don't order by application alone. Fits 2018 model can include two different engine options. Check the part number.
2. Don't assume new means verified. A part can be wrong, damaged, or missing a thermal coating. Inspect it before install.
3. Don't ignore lead time. A pressure differential transmitter might be a stock item at one supplier, but a specific model can take a week or more. If you wait until the old one fails, the building could be down.
4. Don't treat who changes headlight bulbs as a joke. It's a screening question. If the person you assign doesn't know how to remove the bulb connector without breaking it, you'll have a bigger job on your hands.

Do I have mixed feelings about this process? Yes. Part of me wants to simplify everything and use one parts vendor for all maintenance. Another part knows that redundancy saved us during a supply chain delay in 2024. I've settled on a primary parts supplier plus one backup for each category.

The goal is simple: know the part number, know who does the labor, and write down the trigger before the box is open. That's the whole checklist. It doesn't make maintenance exciting, but it keeps the parking lot dry and the office lights on.