Understanding How Your Roofline Lights Work
Series vs. Parallel Wiring: Before you begin troubleshooting, determine whether your lights work in series or parallel:
G30, C9, C7 and G20 bulbs with E12 or E17 socket power cord from Big Star Lights are wired in parallel. This means if one bulb is missing or not working, the rest of the string will still light up. Each bulb has its own direct path to the power source.
In contrast, with series wiring, removing or losing one bulb disconnects all bulbs beyond it.
Step 1: Check for Power
Start at the Source: If your freshly installed roofline lights won’t turn on, always begin by checking that the outlet provides power.
Testing Outlets:
Use a multimeter or clamp meter to check for voltage.
Alternatively, plug in a device or light you already know works.
If There Is Power: Move to the next section of your installation and continue checking each connection the same way, working methodically down the line.
Step 2: Test Each Connection
Isolate the Issue:
Once you reach the start of your lights, check each connection with your test device or bulb.
If a particular connection is faulty, disconnect and examine it closely.
Common Connection Issues:
Zip Plugs: If you are using zip plugs with SPT-2 flat wire, make sure the prongs are biting securely into the wire. Repeated use can cause prongs to fold over instead of making contact.
You can try carefully bending the prongs back or simply swap in a new plug for a reliable fix.
Step 3: Check Bulbs and Sockets
Quick Fixes:
A bulb that isn’t lighting is rarely burnt out—it’s often just loose. Try screwing it in more tightly.
Inspect the bulb base for corrosion, and clean gently as needed.
Socket Issues:
Like zip plugs, E12 & E17 sockets on our Socket Power Cord and Spool products have prongs that need to bite into the wire.
If a socket is old, worn, or was stapled to a hard surface, the prongs can become dislodged or lose contact with the wire.
In these cases, replacing the faulty socket is necessary for a lasting repair.
If you've got several bulbs out or not working on a string of E12 or E17 socket wire
Get a bulb that you know is working. Move the working bulb into a socket that had a non working bulb. If the new bulb lights up, it means the original bulb is defective. If it doesn't light up, it means the socket itself is faulty.
Repeat for any other sockets where bulbs are not turning on.
If only a few sockets are not working on a string of E12 or E17 Socket Power Cord, then you can replace the individulal sockets
Final Tips
Work slowly and test each change as you go—this helps pinpoint the exact location of the problem. Most issues stem from loose bulbs, faulty connections, or worn plugs and sockets.
If you’re stuck, our customer support team is always happy to help!