Brake Light Works But Shuts Off

[XCScott]

Hi, I have a 1985 Spree. About a week ago I ran into tail light problems. When my moped is on and running the tail light is on. When I pull the brake it gets brighter but after about 15-30 seconds the light dims and goes out. Why is this happening and what can i do to fix it??? Thanks

[CharlotteSpreeRider]

How's the battery been working? This kinda sounds like what mine did at idle when I had no battery.

[XCScott]

Brand new battery, works great.

[Wheelman-111]

Greetings:

It's the ECM! The computer reads the braking signal, and decides you've obviously spent far too much time on the brakes, and thoughtfully disengages them for you, Dave.

Sinceriously, consider hotwiring the two wires to and from the handlebar switch. It sounds like it could be corrosion there. When the Verdegris warms up, conduction falters, then fails. A common occurrence with little switches. Bigger ones like the horn switch can carefully be dismantled and cleaned up. Not so sure about those tiny ones behind the brake levers.

[Bear45-70]

Sounds like a bad ground to me, probably from corrosion. Why, because both the tail and brake light come on then go out and they use the same ground.

[Wheelman-111]

Greetings:

If it's all the lights - that part wasn't clear - then I agree with The Bear, as usual. The reason is the same - corrosion somewhere along the metal-to-metal current path.

[Bear45-70]

With a little more though I also think it could be a dirty or corroded socket.

[Clivester]

Do both the tail and brake go out, or just the brake?

If its just the brake try switching the bulb. Could be just a bad filament that expands and breaks continuity when hot. If both lights go out I'd guess its most likely a corroded socket.

[XCScott]

"Do both the tail and brake go out, or just the brake?"

No only the brake light, when I release the brake the tail light comes back on.

[Clivester]

Any resolution to this?

[Bear45-70]

"Do both the tail and brake go out, or just the brake?"

No only the brake light, when I release the brake the tail light comes back on.

So while the brake is on both lights are out. That means the ground is bad because it will only handle the current for one bulb.

[XCScott]

Problem solved... I was sold a faulty light bulb that had a bad filament. I bought a new one and now it is fine. Thanks all for the help.