Modern Vespa

So if anyone seen my other post i recently restored a px and i had a question about the brake light. I put in a new wiring harness and im unsure if the brake light is working correct.When bike is running the tail light is on as it should be but when i hit the brake the lights in the brake light go out then back on fast(the top and the bottom lights are on) .Should it be like newer bikes and the top bulb goes brighter when brake applied or is this just the way older bikes are? I dont remember how it was b4 the rebuild.

It isn't that the "light gets brighter," but that there are two separate filaments; one each for brake and for running.

Remove your lens and verify what is actually happening when you hit the switch.

Place a mirror on so you can see the back of the bike. That's what I did to see if mine was working properly after a bulb went out a few weeks ago.

Give it throttle while applying the brake. Note what happens.

Thank you for the feedback.Just was not sure if that is the way it worked, now i know what to check. I know the other filament is not coming on will have to check bulb and hookups.

After looking at the bulbs they are both single filament.I guess my question is which one is the brake light? Both stay on at all times the top one cuts of and back on real fast when brake is applied which i guess answers my question, the top is the brake ? Can someone with a older P series tell me what my light back there should be doing? Mine is a 82 px150.

Wires connected correctly at the taillight?

Make sure you have the 3 taillight wires on the proper tabs. If all the bulbs work... that's where I'd be focusing my energy.

I know but i need to know what i am trying to make the light do. Does the top one only light up when the brake is applied and the bottom one stays on or is it opposite?