Okay, it sounds like you've done your research to try and get the right bulbs, but something's still not quite right. Here's a breakdown of the common issues and how to troubleshoot

Possible Causes and Solutions

1. Compatibility Issues (Even with "Direct Replacement") Ballast Type

Not all ballasts are compatible with all direct-fit LED T8 tubes. Even though the LED tubes say "ballast compatible," it can depend on the specific ballast type in your fixture. There are different kinds of ballasts (Instant Start, Programmed Start, Rapid Start). The LED tube packaging may have a list of compatible ballasts or ballast types.

Shunted vs. Non-Shunted Lampholders (Tombstones)

This is a very common issue.

Fluorescent Fixtures

Fluorescent T8 fixtures usually have shunted tombstones. This means the two pins of each lampholder (tombstone) are internally connected.

LED Tubes

Many direct-fit LED T8s require

non-shunted tombstones when used with a ballast. This is because the LED tube internally uses the two pins for power delivery. Symptoms

If you have shunted tombstones and put in an LED tube that requires non-shunted, you can get the flashing you describe, or no light at all.

Voltage and Current

While the wattage is comparable, LED tubes may have different voltage and current requirements compared to your original fluorescent tubes when running off the ballast.

Solution



Inspect Your Tombstones

This is the FIRST thing you should do. Turn off the breaker to the fixture. Remove the bulbs. Look very closely at the tombstones (the sockets where the bulb pins go). Are the two slots/holes on each tombstone connected internally? You can usually see a small metal bar connecting them.

If They Are Shunted

You have a few options:

Rewire the Fixture (Ballast Bypass)

This is often the best long-term solution. It involves removing the ballast entirely and wiring the LED tubes directly to the line voltage. This eliminates ballast compatibility issues, and it also eliminates the eventual cost of replacing a failing ballast. This is a moderate electrical project, and requires understanding basic electrical wiring.

If you're not comfortable, hire a qualified electrician. Make sure you purchase "Type B" LED T8 tubes that are designed for ballast bypass. These are sometimes called "double-ended" because they use both sides of the tube for wiring. Replace the Tombstones

You can replace the shunted tombstones with non-shunted ones. This is often done in conjunction with rewiring the fixture (ballast bypass).

Try Different LED Tubes

Check the packaging of your LED tubes very carefully. Look for specific statements about compatibility with shunted tombstones. Some LED T8s are designed to work with shunted tombstones in ballast-compatible mode, but they may be more expensive or harder to find.

Check the Ballast Information

If you can see the ballast inside the fixture, look for a label. Note the manufacturer and model number. Then, search online for the ballast's specifications. See if it lists compatible LED tubes or even ballast types.2.

Ballast Age or Failure Old Ballasts

Ballasts have a lifespan. If your fixtures are old, the ballast may be weak or failing. Even if the ballast is technically "working" for a fluorescent tube, it might not provide the correct voltage or current for the LED tube.

Incorrect Voltage or Current

LED tubes are more sensitive to voltage fluctuations and current variations than fluorescent tubes.

Solution



Try a New Ballast (If Staying Ballast-Compatible)

If you want to continue using the ballast, you could try replacing it with a new one that is known to be compatible with LED tubes. Again, check the LED tube packaging for recommended ballasts. This is often not the best solution as its just delaying the inevitable rewiring.

Bypass the Ballast (Best Option)

As mentioned above, rewiring the fixture to bypass the ballast is usually the best long-term solution.3.

Installation Issues Incorrect Orientation

Some LED tubes have a specific orientation. One end might be labeled "Line" (L) and the other "Neutral" (N), or it might have an arrow indicating the correct direction. Make sure you're inserting the tube correctly.

Poor Contact

Make sure the pins on the LED tube are making good contact with the tombstones.

Solution



Check Orientation

Look for markings on the LED tube and make sure you're inserting it correctly.

Clean Tombstones

Use a small brush or a cotton swab dipped in rubbing alcohol to clean the contacts inside the tombstones.

Slightly Bend the Pins

If the pins seem loose, you can very gently bend them outward slightly to improve contact.

Be careful not to break them.4. Defective LED Tubes It's possible you got a bad batch of LED tubes.

Solution



Test in Another Fixture

If possible, try the LED tubes in a different fixture that you know is working properly.

Return and Exchange

If you suspect the LED tubes are defective, return them to Home Depot and get a replacement.

Recommended Troubleshooting Steps1. Safety First

Turn off the breaker to the garage circuit before doing any work on the fixtures.2.

Inspect Tombstones

Carefully examine the tombstones to determine if they are shunted or non-shunted. This is the key to knowing what to do next.3.

Check Ballast Label

If you can, get the manufacturer and model number of the ballast and look up its specifications online.4.

Try One Fixture at a Time

Focus on troubleshooting one fixture completely before moving on to the others.5.

Ballast Bypass (Most Likely Solution)

If you're comfortable with basic electrical wiring, strongly consider rewiring the fixtures to bypass the ballast. This will eliminate most of the compatibility issues and provide a more reliable and efficient lighting solution. Purchase Type B "double-ended" LED T8 tubes for this purpose.6.

When in Doubt, Call an Electrician

If you're not sure about any of these steps or are uncomfortable working with electricity, hire a qualified electrician to diagnose and fix the problem.

Important Considerations Energy Savings

While direct-fit LED tubes can be convenient, they often don't provide as much energy savings as rewiring the fixture and bypassing the ballast. The ballast itself consumes some power.

Longevity

Bypassing the ballast removes a potential point of failure, which can extend the lifespan of your lighting system.*

Future Proofing: Rewiring the fixture makes it easier to replace LED tubes in the future without having to worry about ballast compatibility.By following these troubleshooting steps, you should be able to identify the cause of the problem and get your garage lights working properly. Good luck! Flag for review