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Mon Jul 29, 2024 10:04 am

So my brake lights are not working on my 1959 bug, the taillights work and the blinkers work. I have tested the wires that hook onto the brake light switch and they have voltage, I tested the brake light switch (this switch is brand new) and no voltage but I am getting continuity, not totally sure what that means but looking for any help to get these working again.

Mon Jul 29, 2024 11:24 am

Not enough information to go off of. For starters, we need to know if the car is all original style for a '59 (snowflake tail lights, six wire turn signal, etc) or has it been modified in any meaningful way. Were the brake lights working at some point in your ownership or have they never worked? If they worked previously, what was done to the car in the interim since they worked to now not working? How are you testing the brake light switch (be specific)?

Mon Jul 29, 2024 12:47 pm

So they were working before, not too sure when they stopped working. The car is snowflake lights, now a 12 volt system (done before I owned it), I have had the car converted to a 2 system disc brakes. I have tested the switch and wires with a multimeter, hopefully this helps.

Mon Jul 29, 2024 12:50 pm

Brake light switches are prone to failure, and new ones are often defective.
Remove both wires, connect them together and see if you brakes lights come on. If they do, it's the switch. If not, the problem is elsewhere.

Check easy/cheap stuff first, like correct bulbs and proper light assembly grounding.

Mon Jul 29, 2024 2:02 pm

As above, and do the switch test first before you start messing with the snowflakes bulbs and grounds. Make sure the fuse is clean and has good connection.

Mon Jul 29, 2024 2:30 pm

So I take the 2 wires off the switch and touch them together and nothing happens, no brake lights come on.

Mon Jul 29, 2024 2:56 pm

Next step... with them still disconnected from the switch, but NOT to each other... is one hot?

If so, bad switch.

If you have positive voltage to one side, but no light, trace the other wire and find out what it's hooked up to.

Mon Jul 29, 2024 3:11 pm

So I used my multimeter to test the wires and I'm getting a 12V reading from them, when I test the switch with the multimeter, I get no voltage reading with pushing on the brake but when I put the meter on continuity, I get the buzzing from the switch when pressing the brake pedal.

Mon Jul 29, 2024 4:28 pm

Did you do the tests I suggested?
You are not clear what you are testing in your latest post.

Mon Jul 29, 2024 9:24 pm

broncos73084 wrote: So they were working before, not too sure when they stopped working. The car is snowflake lights, now a 12 volt system (done before I owned it), I have had the car converted to a 2 system disc brakes. I have tested the switch and wires with a multimeter, hopefully this helps.
With your dual circuit master cylinder, are you using one or two switches? Are your brake switches two or three prong? Do you have any additional wires going to the switch(es) than just a single wire coming from the fuse block and a single wire going back to the tail lights?

When you say you tested the wires with a multimeter, are you saying that you have verified with your meter that one of the wires at the switch does in fact have continuity all the way back to the brake light bulb sockets at the tail light assemblies? Without touching the brake pedal, when you checked for power were you seeing 12v at one wire or both wires?

I must agree with KTPhil, your description of what and how you're testing things is lacking in clarity.

Tue Jul 30, 2024 7:20 am

So the switch is a 2-prong switch and there's only 1. There are 2 wires that connect directly onto the 2 prongs, those 2 wires that I tested and got a 12V reading. The switch itself I get no V reading from it but do get continuity from the switch. I'm sorry without the clarity, don't know a ton about car wiring and I'm not very mechanically inclined, may just have to take it somewhere to get it figured out.

Tue Jul 30, 2024 7:48 am

This is a VERY simple system. If you get positive voltage getting to the brake switch with ignition in the "run" position, and no voltage "leaving" the switch when the pedal is pressed down, then can only be one of two things:
1. switch is bad

2. fluid pressure is too low to activate the switch, a brake problem

Once positive voltage "leaves" the switch under those conditions, it becomes a simple wiring/bulb issue if the brake lights don't operate.

Tue Jul 30, 2024 9:00 am

broncos73084 wrote: There are 2 wires that connect directly onto the 2 prongs, those 2 wires that I tested and got a 12V reading.

This is still very ambiguously worded. Are you getting 12V on both poles with your foot ON or OFF the brakes?

Tue Jul 30, 2024 9:27 am

So I'm getting 12V from the wires, the switch I'm getting no V reading at all no matter if I'm pushing in the pedal or not. So the wires that hook onto the switch prongs are live and getting 12V, but the switch is not getting any reading at all.

Tue Jul 30, 2024 9:36 am

broncos73084 wrote: So I'm getting 12V from the wires, the switch I'm getting no V reading at all no matter if I'm pushing in the pedal or not. So the wires that hook onto the switch prongs are live and getting 12V, but the switch is not getting any reading at all.

So, you're saying with both wires disconnected from the switch, they are both hot with 12V?

Tue Jul 30, 2024 9:43 am

Correct

Tue Jul 30, 2024 2:01 pm

Trust me... I'm struggling to understand as well as the next guy...

but... if you took both wires off the switch,
connected 1 of your meter leads to one of the switch wires,
and the OTHER meter lead to the OTHER switch wire...

If your showing (12ish volts) voltage on your meter, you have a complete circuit that SHOULD light your brake light.

Tue Jul 30, 2024 4:45 pm

Which now begs the question of how the meter probes are being applied during the voltage testing.

If the negative probe is applied to a good chassis ground and when the positive probe is applied to each of the two wires separately we are showing 12v present at each one, then either we have an incorrect circuit wire present at the master (shouldn't be likely if the brake lights did previously work), or we have power backfeeding from the tail light assemblies. In this case the first thing to check is if the correct two filament bulb is installed in each snowflake assembly and that the bulb holder contacts aren't getting crossed up somehow.

@broncos73084
How the wire testing is being done is important, hence why it's necessary to be as specific and detailed as possible when describing how you are doing your troubleshooting, especially when you're inexperienced in how to do so. The electrical systems on these cars are pretty close to as basic as you can get, but one still needs to learn and understand how an electrical system works and therefore how to go about testing it to find what needs to be done to fix a problem. I'd recommend reading through the information at the links below. Sadly, many of the associated pictures to illustrate concepts in the text are gone now, but the textual information is still a decent intro to auto electrical and various tests of them.
https://www.hagerty.com/media/maintenance-and-tech/automotive-circuit-failures/
https://www.hagerty.com/media/maintenance-and-tech/how-to-use-a-multimeter/
https://www.hagerty.com/media/maintenance-and-tech/multimeter-part-2/
https://www.hagerty.com/media/maintenance-and-tech/measuring-resistance/
https://www.hagerty.com/media/maintenance-and-tech/measuring-current/
https://www.hagerty.com/media/maintenance-and-tech/measuring-voltage-drop/