1929 Dodge vs. new rear tail , turn and brake lights

[Bob Zetnick]

I have a 1929 Dodge that got rewired last year just before a move to Colorado. I am trying to get my car ready for inspection, so I can get new plates. I am having several wiring issues, but only a couple have to do with me getting an inspection. I got some 2-wire turn signals for the rear that are supposed to have stop, tail and turn capability. I wanted these to be used in conjunction w/ the original back light for stop and tail capability. I am having 2 problems. First, the original rear light just has a light glow, hardly visible and when I turn on the headlights even that glow in the original rear light goes out (a short?) Secondly, the new turn signals seem to work for brake and turn signals, but not for tail lights. I have been reading a lot of suggestions on hot rod and trailer sites, some of which say I need a 3-wire to 2-wire converter. Anyway, I did a wiring diagram below that interpolates between the original wiring diagram, the 'Signal-Stat' 900 series turn signal wiring diagram and a few online wiring diagrams. I don't know if this diagram is correct or if any wiring guys here can help me. BTW, this is a 6 volt system. Thanks

[JACK M]

I would almost bet that the light glow is a bad ground.

I am looking at your diagram and see that your brake light switch doesn't run to the turn sig switch. Rather you are supplying voltage from the clum to the turn switch before the brake switch and it should be after. Which I would presume that brake lights would always be on when the clum switch is on.

The turn switch is supposed to tell the car which brake lights and turn signals to light up.

Try taking the wire off that runs from the brake light switch to the stop light and let it hang, then take the wire that goes to the turn switch off of the power side of the brake light switch and put it on the switched side of the brake light switch where you just disconnected the "stop" wire.

I see a couple of other things on this diagram that are probably giving you problems. That wire on the back that is marked stop/tail lights. I think that is supposed to be tail lights.

I suspect that if you eliminate that wire at the brake switch I suggested above you wont be doubling up the brake and tail lights.

I am not sure about the center light marked tail/license I think this may take care of itself as well when you fix that brake light power supply to the correct side of the brake switch. If you want that to have a brake light function you could put that on the switched side of the brake switch.

 

Brake light and turn signal should be the same element.

I am sure that I have the turn signal wiring diagram that would give the colors so if you still have trouble I can reference that.

 

Just had a thought, just cut the wire between where it branches to the center light and the stop/tail wire. Move the wire highlighted above and all should be well.

Hope this helps.

 

[JACK M]

I don't want to confuse you, just do the two things that I highlighted in orange.

[Bob Zetnick]

5 minutes ago, JACK M said:

I don't want to confuse you, just do the two things that I highlighted in orange.

Thanks Jack. Let me wrap my head around your comments as I'm not an electrical guy by any means.... I might have some more questions for you while looking at the diagram.

 

[Spinneyhill]

Part of it might be that I see only one circuit for stop and tail lights. Should there be separate wires? i.e. there is a dual filament bulb so it needs two feeds? I think you would then cut one of them intermittently for the blinkers? We are required, in general, to have a separate blinker bulb and not flash the brake light.

[JACK M]

19 hours ago, Bob Zetnick said:

Thanks Jack. Let me wrap my head around your comments as I'm not an electrical guy by any means.... I might have some more questions for you while looking at the diagram.

 

 

Any time Bob, Basic wiring comes pretty easy to me.

And I just recently hooked one of those aftermarket signal switches.

I have found on these old cars that grounds and parts that the grounds pass through (fenders and such) can be a bugger to figure out for some.

[Bob Zetnick]

21 hours ago, Spinneyhill said:

Part of it might be that I see only one circuit for stop and tail lights. Should there be separate wires? i.e. there is a dual filament bulb so it needs two feeds? I think you would then cut one of them intermittently for the blinkers? We are required, in general, to have a separate blinker bulb and not flash the brake light.

Thanks...yeah, I thought the same thing, but a couple of online sites as well as the turn signal switch directions told me to wire that way, but I think you and Jack may have figured out that is part of the problem.

[Bob Zetnick]

2 hours ago, JACK M said:

 

Any time Bob, Basic wiring comes pretty easy to me.

And I just recently hooked one of those aftermarket signal switches.

I have found on these old cars that grounds and parts that the grounds pass through (fenders and such) can be a bugger to figure out for some.

Jack, I've been looking at your notes for a couple of hours...I think that you and Spinneyhill are saying the same thing in that the stop light ties into the turn signal and not the tail light.....I went by a couple online sites and direction from the turn signal switch mfgr. I had no idea that the side of the brake switch mattered (I'll have to test as master cylinder is out being resleeved / rebuilt)...how can you tell the power side from the switch side? I will say on the original (center) light I've grounded it w/ a jump wire and no difference, but maybe switching some of these wires may give different results. I may have to take you up on more questions too as dome light and brights on headlights doesn't work either.....dome light is especially problemic as I now have new upholstery installed (I have a feeling the guy who put in upholstery disconnected screwed in ground when installing headliner)

[Bloo]

There are two common ways of handling the turn signal/stoplight issue.

 

The first is to have a separate filament (or whole bulb) for the rear turn signals. In the modern era most Asian cars do this. 39 Buick is another example.

 

In this scenario, the turn signals are a completely separate circuit, and not tied into anything. The switch is just a simple switch.

 

The second method shares the stoplight filament with the turn signals. This is how most American cars are wired from the time factory turn signals became common (early 50s) through the 80s or 90s at least. Usually a dual filament bulb is used. There is a dim filament and a bright one. The dim one is for taillights ONLY. The bright one is shared between the turn signals and the brakelights.

 

It looks like you are using the second method.

 

To share the filaments, the turn signal switch has to be much more sophisticated. Here's how it works:

 

6V is fed through the flasher (in through one pin and out through another) to the turn signal switch. In the switch, one front signal bulb gets connected when you turn a signal on.

 

6V is fed through the brake light switch to the turn signal switch, from there the switch connects it to the bright filament of both rear bulbs when no signals are on. Brake lights work as normal.

 

When you turn on a signal, the turn signal switch disconnects ONE rear bulb from the brakelight switch, and connects it to the flasher.

 

The third pin on the flasher is for an indicator inside the car. If there is only one indicator bulb, it connects to the third flasher pin.

 

If there are 2 indicator bulbs inside the car, one for right and one for left, they connect to the front signals, and the third flasher pin is not used.

 

Yes, there need to be completely separate wires all the way from the turn signal switch to each bright filament in the rear bulbs. Without this, there would be no way for the turn signal switch to disconnect ONLY ONE bright filament from the brakelights and connect it to the flasher when you turn a signal on.

 

As JACK M mentioned, pay attention to the ground path from ANY light back through the body or frame or whatever. If the grounds are bad, the problems will be bizarre.

Edited May 22, 2019 by Bloo (see edit history)

[Bob Zetnick]

3 hours ago, Bloo said:

There are two common ways of handling the turn signal/stoplight issue.

 

The first is to have a separate filament (or whole bulb) for the rear turn signals. In the modern era most Asian cars do this. 39 Buick is another example.

 

In this scenario, the turn signals are a completely separate circuit, and not tied into anything. The switch is just a simple switch.

 

The second method shares the stoplight filament with the turn signals. This is how most American cars are wired from the time factory turn signals became common (early 50s) through the 80s or 90s at least. Usually a dual filament bulb is used. There is a dim filament and a bright one. The dim one is for taillights ONLY. The bright one is shared between the turn signals and the brakelights.

 

It looks like you are using the second method.

 

To share the filaments, the turn signal switch has to be much more sophisticated. Here's how it works:

 

6V is fed through the flasher (in through one pin and out through another) to the turn signal switch. In the switch, one front signal bulb gets connected when you turn a signal on.

 

6V is fed through the brake light switch to the turn signal switch, from there the switch connects it to the bright filament of both rear bulbs when no signals are on. Brake lights work as normal.

 

When you turn on a signal, the turn signal switch disconnects ONE rear bulb from the brakelight switch, and connects it to the flasher.

 

The third pin on the flasher is for an indicator inside the car. If there is only one indicator bulb, it connects to the third flasher pin.

 

If there are 2 indicator bulbs inside the car, one for right and one for left, they connect to the front signals, and the third flasher pin is not used.

 

Yes, there need to be completely separate wires all the way from the turn signal switch to each bright filament in the rear bulbs. Without this, there would be no way for the turn signal switch to disconnect ONLY ONE bright filament from the brakelights and connect it to the flasher when you turn a signal on.

 

As JACK M mentioned, pay attention to the ground path from ANY light back through the body or frame or whatever. If the grounds are bad, the problems will be bizarre.

Thank you! Like I told Jack I really don't know about auto wiring ,so will have to print this out and wrap my head around it w/ the car. all my rear lights have 2-filament bulbs...one question though is how do you know a dim filament from a bright one? I just thought each filament had its own brightness, but sometimes both filaments came on and that's what made them bright....hmmmm

[Spinneyhill]

Usually dual filament bulbs are something like 5/20 W. The bigger filament is usually the brighter one.

 

Do yours have offset pins near the base? That way, they bulb goes in the right way. The bulbs are called BAY15D or BA15D (15 = diameter in mm, D= dual filament). BAY = offset pins, BA = opposite pins.

Edited May 23, 2019 by Spinneyhill (see edit history)

[Bloo]

Yeah, if you look inside, the bright one is bigger!

 

If both come on, either something is wired incorrectly, or there is a bad ground. Usually it means a bad ground.

[JACK M]

As for the brake light switch, Your diagram shows the lead to the sig switch is on the same side as the power supply. Hence the turn signal device is not switched, but on all of the time.

Two posts on the BL switch, one in and one out. So you are turning on the power with the clum switch (in) the other would be out and would supply the signal device. This is usually called a canceling device.

You are trying to power the stop lights directly, They need to be supplied their power thru the canceling device.

The canceling device will tell which brake light needs to become a turn signal. It would appear that you have that right but are over riding at the BL switch.

Edited May 23, 2019 by JACK M (see edit history)

[Bob Zetnick]

14 hours ago, Spinneyhill said:

Usually dual filament bulbs are something like 5/20 W. The bigger filament is usually the brighter one.

 

Do yours have offset pins near the base? That way, they bulb goes in the right way. The bulbs are called BAY15D or BA15D (15 = diameter in mm, D= dual filament). BAY = offset pins, BA = opposite pins.

My turn signals have sealed beam bulbs like photo, my original stop / tailight has straight pins, but I do see a larger filament....I guess I just test what contact / wire goes to larger filament. Any ideas on the sealed beam?...maybe just test also....

[Bob Zetnick]

14 hours ago, Bloo said:

Yeah, if you look inside, the bright one is bigger!

 

If both come on, either something is wired incorrectly, or there is a bad ground. Usually it means a bad ground.

I do have a larger filament on the original tail / stoplight and one filament is larger. As my bulb has straight pins, I'll just test which contact makes the large filament light up. This original light just has a soft glow, so may be a ground issue. My turn signals are sealed beam bulbs, so I guess I just test contacts there too.

[Bob Zetnick]

1 hour ago, JACK M said:

As for the brake light switch, Your diagram shows the lead to the sig switch is on the same side as the power supply. Hence the turn signal device is not switched, but on all of the time.

Two posts on the BL switch, one in and one out. So you are turning on the power with the clum switch (in) the other would be out and would supply the signal device. This is usually called a canceling device.

You are trying to power the stop lights directly, They need to be supplied their power thru the canceling device.

The canceling device will tell which brake light needs to become a turn signal. It would appear that you have that right but are over riding at the BL switch.

My brake light switch is like this.....not sure if I have the same height in contacts though. So, how do you tell which is the power side vs. switch side...is it heights of contacts? I should get my master cylinder w/ brake light switch today, then I can look to see exactly what I've got as a switch.

[Bloo]

You have sealed beams for signal lights?!!

 

I take it then they are separate from the brake lights. That changes everything. There would not need to be any interconnection between those and the brake lights.

 

For brakes:     6v >> brakelight switch >> large filaments in tail/stop light housings.

 

For signals:    6v >> flasher >> signal switch >> 4 wires, one each, to 4 signal lights

 

This assumes a signal switch that has separate wires for front and rear. If you have separate wires, use them, because the sealed beams probably draw a lot of current.

 

The separate wires for front and rear are not necessary though in a system like this. If you dont have them, just hook the right wire to both right lights, and the left wire to both left lights.

 

How many watts are those sealed beams? If they are a lot more than a signal light bulb, it is gonna be really hard on the signal switch, and you might need a heavier duty flasher.

Edited May 23, 2019 by Bloo (see edit history)

[Bob Zetnick]

5 hours ago, Bloo said:

You have sealed beams for signal lights?!!

 

I take it then they are separate from the brake lights. That changes everything. There would not need to be any interconnection between those and the brake lights.

 

For brakes:     6v >> brakelight switch >> large filaments in tail/stop light housings.

 

For signals:    6v >> flasher >> signal switch >> 4 wires, one each, to 4 signal lights

 

This assumes a signal switch that has separate wires for front and rear. If you have separate wires, use them, because the sealed beams probably draw a lot of current.

 

The separate wires for front and rear are not necessary though in a system like this. If you dont have them, just hook the right wire to both right lights, and the left wire to both left lights.

 

How many watts are those sealed beams? If they are a lot more than a signal light bulb, it is gonna be really hard on the signal switch, and you might need a heavier duty flasher.

This is the spec. for the sealed beams. 

U-4414R 5" dia., PAR 36, Signal Lamp Red, 18 watts, 275 candlepower, screw terminal base, 100 hours life

There are 2 contacts, so I assumed the 3 functions of turn, stop and tail could work and that's what I really want. These were sold off of an old 6V firetruck...the actual bulbs are expensive and not made anymore; at least in red. I do have brand new lights that are supposed to work for turn, stop and tail that are 6v and I got from Rodtiques. I guess my point is if I rewire and my current lights may not work for all 3 functions and that I may not be able to find bulb replacements in the future, then I may use the new lights on the car and keep the ideas from the earlier posts about wiring. As I said before it's hard to wrap my head around this as I'm not an electrician, so I pretty much understand the earlier posts and would hate to switch gears in thinking. I appreciate your responses. BTW, on the brake light switch that I posted above do you know which side is the hot / power side? Does it have to do w/ the height of those contacts?

[Bloo]

These only have one filament and it is a bright one. You could conceivably combine stop and signal (using the method we were talking about several posts back), but you would still have to have something else for a taillight.

 

A double filament stop/taillight bulb has 3 connections. The two little contacts are both hot, one is for the bright filament and the other is for the dim one. The base is the third contact. Both filaments ground through the base.

 

On these Par36 bulbs, the two terminals are hot and ground and there is only one filament. Also, it doesn't matter which terminal you use for ground.

 

The brakelight switch wont care which terminal is which.

 

On the flasher, however, you will have to use the correct terminals for each wire.

Edited May 24, 2019 by Bloo (see edit history)

[Bob Zetnick]

9 hours ago, Bloo said:

These only have one filament and it is a bright one. You could conceivably combine stop and signal (using the method we were talking about several posts back), but you would still have to have something else for a taillight.

 

A double filament stop/taillight bulb has 3 connections. The two little contacts are both hot, one is for the bright filament and the other is for the dim one. The base is the third contact. Both filaments ground through the base.

 

On these Par36 bulbs, the two terminals are hot and ground and there is only one filament. Also, it doesn't matter which terminal you use for ground.

 

The brakelight switch wont care which terminal is which.

 

On the flasher, however, you will have to use the correct terminals for each wire.

Got it! Thanks a lot! I'm going to remove the sealed beam lights and use the new set of lights that will work for all 3 functions. I've got enough info to start this weekend.

[JACK M]

When you talk about all three functions. Stop, turn, and brake.

The bright filament is both the brake and turn signal. The dimmer filament is tail lights.

As I mentioned before, you make the brake light switch send its juice to the canceling device and it will make sure your brake lights are working, If you have a turn signal in use it will flash that brake light and leave the other side solid on for brakes.

I would use some regular dual filament tail light assemblies. And yes, the base of those bulbs are the ground. Grounds can be confusing.

Some old guy I know used to say that "90% of all electrical problems are groundless".

[Bob Zetnick]

32 minutes ago, JACK M said:

When you talk about all three functions. Stop, turn, and brake.

The bright filament is both the brake and turn signal. The dimmer filament is tail lights.

As I mentioned before, you make the brake light switch send its juice to the canceling device and it will make sure your brake lights are working, If you have a turn signal in use it will flash that brake light and leave the other side solid on for brakes.

I would use some regular dual filament tail light assemblies. And yes, the base of those bulbs are the ground. Grounds can be confusing.

Some old guy I know used to say that "90% of all electrical problems are groundless".

Thank you! Yes, I will go that route. I'll have to trade out my existing sealed beam signals for a new set of signals I have that will do all 3 functions. I thought the 2 contacts on my sealed beam signals would do the same thing, but apparently not according to Bloo. Anyway, have the weekend to work on this stuff....may have more questions or may be a breeze...I appreciate all your help!

[JACK M]

Have fun !!!