Brake light problem

[Nomadtrebor]

I recently bought my first model A, (1930 Phaeton)
I'm having a problem with my brake light
all lights seem to work properly with the steering wheel lever switch, but when i step on the brakes the tail lights go out and no brake light. ? ? ?
I suspected the brake light switch, but when tested it seems to be working properly, although i question which wire should be connected to it ? Positive or Negative ?

 

[Tacoma Bob]

Are you 6 volts or 12 volts. Are you positive or negative ground?

 

[Nomadtrebor]

6 volt positive ground

 

[rocket1]

If it is the original 6 volt system it is positive ground,to test the stoplight switch put a jumper between the 2 connections at the stoplight switch,the brake light should go on,some repro switches are defective,short out inside when activated.

 

[katy]

when i step on the brakes the tail lights go out and no brake light. ? ? ?

What happens when you step on the brakes and the tail lights are not on?

 

[Nomadtrebor]

The brake lights do not come on at all

 

[Y-Blockhead]

First thing I would do is check your grounds. Sounds like when you step on the brake light the voltage is trying to backflow thru the running light instead of going to ground. Hence the running light goes out and the brake light does not light.

Try connecting a jumper wire from a known good ground (bumper, frame, etc,) to the light housing to check.

Bad grounds cause weird things to happen.

 

[Patrick L.]

So if the brake switch has been checked and seems to be working properly, there is power at the switch and then thru the switch when pedal is depressed ?

Is there power to the brake bulb with pedal depressed ? If so, I'd recommend checking grounds.

 

[katy]

I question which wire should be connected to it ? Positive or Negative ?

The feed to it should be negative.

 

[ryanheacox]

I was watching a youtube vid the other day and when the guy stepped on the brakes the stop light came on and tail light turned off. Foot off the brakes and the tail light would come back on. Not sure what was going on there but it might be a similar problem.

 

[Will N]

Do you have a turn signal installed that works on the original brake light bulbs? If so, the brake lights are wired through the turn signal wiring harness, and you may have some wires crossed up.

 

[Bob C]

I was watching a youtube vid the other day and when the guy stepped on the brakes the stop light came on and tail light turned off. Foot off the brakes and the tail light would come back on. Not sure what was going on there but it might be a similar problem.

Most likely a bad ground.

 

[The Master Cylinder]

First thing I would do is check your grounds.

If so, I'd recommend checking grounds.

Most likely a bad ground.

I say bad ground.

That's 4 votes for bad grounds now...