no brake lights
 

i have a late 1931 model A that runs great. Haven't done anything electrical to it since I got it and I was hoping this scenario would ring a bell for the many experts out there. When I turn on the cowl lights or headlights, both tail lights and stop lights work. However when I press the brake pedal alone neither brake light works and the amp meter doesn't move. I would appreciate any recommendations on how to start troubleshooting. Many thanks

Re: no brake lights
 

That does sound a bit tricky. You say the brake lights work properly if the tail lights and tail lights are on, but do not work at all if headlights and tail lights are not turned on. Sounds like the power going to your brake light switch might be coming from your headlight switch and not off the battery. It should be wired so that as soon as the key is in a run position you have power to the brake light. You might want to try to follow your wire form the brake light switch back to its source. Maybe at one time the ignition switch was replaced and not wired back correctly. I am no expert when it comes to electrical, but this is what it seems to me.

Re: no brake lights
 

Thank you, i will definitely check that out.

Re: no brake lights
 

For some unknown reason Henry routed the power to the stop light switch through the light bale, where there can be electrical faults due to the nature of the construction, especially if it is a reproduction. If you are out on the road and a short circuit occurs in the light bale and blows the fuse you can disconnect the wire that runs from the generator to the light bale, and continue on your way during daylight hours. However, you will not have stop lights. A very easy and prudent modification to incorporate is to disconnect the wire at the stop light switch that comes from the light bale, fold it back and wrap black take around it. Run a new wire from where the old wire was removed to the fuse or to one of the terminal lugs on the firewall. this makes the stop light switch independent from the light bale and very easy to trouble shoot. It also allows you to continue on with power disconnected to the light bale during daylight hours and still have stop lights.

Tom Endy

Re: no brake lights
 

How about the bulbs (6Volt)? may have shorted out and blown! oh I see it says work may be the wire to the brake switch or the switch itself.

Re: no brake lights
 

Re: no brake lights
 

Re: no brake lights
 

What Tom says.

Re: no brake lights
 

thank you all for sharing your thought process with me. once i figure out what is going on i will let you know.

Re: no brake lights
 

In my online search for helpful wiring photos/diagrams, i came across this fantastic presentation on model a wiring. here is the link...hope it works, if not do a search for ElectricalSystemAlexJanke

https://www.mafca.com/downloads/Semi...ex%20Janke.pdf

Re: no brake lights
 

Thanks for the link, carol ann, I hadn't seen such a complete and comprehensive article before.

As for your problem, my guess is that the brake switch (green wire) is connected to the same lighting switch terminal as the tail lights (black wire). This is incorrect; the brake switch should be HAT - hot at all times - connected to the same terminal as the generator wire (yellow).

Re: no brake lights
 

I stand corrected. Thanks Y-Blockhead. I was just trying to deduct from the symptoms the original post said that they only worked when the headlights were on.
Eric

Re: no brake lights
 

That link worked for me. I printed the whole thing out on my inkjet printer and will put it in a three-ring binder. Thanks!

Re: no brake lights
 

thanks Badpuppy....i used the multimeter to check voltage across the brake light switch and got nothing; funny thing...when i touched the brake light switch, half of it fell off while half of the empty switch shell was still bolted on. The switch itself was full of goo (grease and dirt). ordered a new one from A&L but i suspect there are some wiring anomalies since the ammeter on the dash appears to be wired in reverse...meaning when the lights are turned on, it shows charging. I love this car and a good puzzle...will keep you posted. thanks for the support which helps me venture out to where i haven't been before!!

Re: no brake lights
 

Ammeter. Is the car 6v or 12v ? How is the battery hooked up, - or + grd ? Alternator or generator ? Once we know that we can figure out the ammeter issue, it'll be easy. It may just need a flash/polarizing.

Re: no brake lights
 

6 volt, positive ground with generator.

Re: no brake lights
 

OK, does it show a charge when running at a fast idle ? I should have asked that before.
With engine running, jump across the cut-out terminals for a second. Then see if the ammeter is correct. If correct, with the fan belt loose, applying power to the generator will cause it to motor slowly in the correct rotation [CW from front]. If this corrects it, fine. And it probably will. If the ammeter reads backwards in everything, charge with lights on and discharge when running, then the wires on the ammeter need to be switched.

Re: no brake lights
 

Generator should be polarized with engine NOT running, to align it with battery polarity. But probably not the cause. Ammeter wire reversal is a common problem for some reason. Just hook it up per Janke's diagrams on the mafca site.

Re: no brake lights
 

I appreciate everyone's help and I will take all your helpful input into my troubleshooting process. I will update this thread after i receive some new parts and i can check things out.
Thanks again,
Carol ann

Re: no brake lights
 

If you get into a "bind", there are many A owners (and at least one thriving club) on the Island. FWIW
Paul in CT