Your Lionel 675 light does not work, you say? Mine didn’t either, but the fix was really simple. You might not even need any parts.
My bulb actually worked–poorly. It flickered like crazy, which told me the bulb was probably OK but wasn’t getting good electrical contact. That tipped me off to the fix.
Start by popping off the front of the locomotive, which has the headlight lens and the locomotive number on it. If you look closely you can see the seam. Grip it by the sides and gently pull straight forward. It’s only held in place by two tension clips.
You’ll notice once you have the front off that there is a socket for the light bulb inside, held in place by another set of clips. Well, it’s supposed to be held in place by that set of clips. If your bulb isn’t working, it might not be.
But first, check the most obvious thing, Pop the light bulb and its socket out of the holder. Make sure the bulb is screwed in tightly. Next, pop the bulb and its socket back into the holder. The bottom of the socket should line up with the bottom of the clip, and it should fit pretty tightly. If it won’t sit in tightly, you can crinkle up a small square of aluminum foil and put it into the holder behind the bulb to tighten the fit a little.
Now snap the front back into place, place the locomotive on the track, and apply power. I’ll bet you see a glowing headlight.
If not, the bulb may be burned out. The 675, 2025 and 2035 use the common 1447 bulb, available on Ebay or at many hobby shops.
You can test the bulb by connecting it directly to a transformer or to a battery. Remove the bulb from the locomotive. Connect one wire to the A post and another wire to the U post. Connect one of the wires to the black base of the bulb, and one to the threaded metallic part. If the bulb doesn’t light, it’s burned out. If it does light, you probably didn’t get the socket into the holder tightly enough.
Why did they design it that way? It’s simple, really–Lionel wanted it to be easy to change the light bulb if it burns out. Unfortunately, due to the way they did it, it’s much easier for the socket to slip out of its holder than it is for the bulb to burn out, so if your Lionel 675 light does not work, it’s more likely to be the holder than the bulb. It was a trade off. Some of Lionel’s competitors handled it in a way that made the light more reliable, but changing the bulb takes 15 minutes. For a kid, the Lionel compromise works a lot better.
If the bulb works outside the locomotive but just won’t work inside it and it snaps in tightly, there may be a problem with the wire running to the motor. If you’re not comfortable disassembling the locomotive and re-soldering or replacing the wire, you may need to have the locomotive fixed at a hobby shop. The likelihood of a bad wire, however, is much lower than the light just bouncing around.
As long as you keep the bulb on the track or on a shelf after repositioning the bulb, it should work reliably. The bulb tends to slip out of place when the train is jostled around in a box. But in the event that it does slip back out, the fix is easy once you know it.