wiring problems

[Ed Fleming]

Has anyone everhooked up brake lights and turning signals on a 48 ply p15 my problem started last week . When I went to get gas some guy followed me in the gas station yelling at me that I had no brake lights . When I checked the centre trunk light . It was working but not all that bright so I got the bright idea to hook up both fender lights to the centre brake light by jumping a wire to both lights . that worked fine but now when I put on my turning signals all three lights flash I have tried every combination of wiring Icould think of with no avail. so if anyone has two or three working brake lights and turning signals I would appreciate how you did it thanks for any help Ed

[BobT-47P15]

It can be done, Ed.

There is a wiring diagram on how to hook those things up correctly.

I've done it, but don't recall at the moment just how it went.

You need double filament bulb connectors in your tail light sockets, with double

filament bulbs. You end up with Taillight, Brakelight, Turnsignal on each side,

and the center thing only works as a 3rd stop light.

And, you also need double filament sockets & bulbs in the parking lights.

However, I figured I don't use the parking lights much.......so I simply unhooked them

from the light connector bar, and use them only for turn signals. Did not need to

change the socket or bulb that way. Clear as mud?????

Edited August 24, 2009 by BobT-47P15

[BobT-47P15]

Here's a diagram for a typical 7 wire system. As you can see, you have

to run one wire from the stop light switch.

[BobT-47P15]

A couple corrections have been pencilled in.

[Young Ed]

Ed what type of turnsignals are you running? If you have the OEM ones with only 3 wires its much more complicated to have 3 brake lights. I've been curious if one could wire in 2 hydralic switches to have one just for the third brake light and the other for the stop and turn lights on the 1/4s.

[greg g]

You should be able to pull two wires for power out from the stop light switch, one for the turn signal, and one for the center lamp. The flasher shouldn't back feed the center light that way, if it does a diode in the line going to the turn signal should solve that problem.

[Ed Fleming]

Ed what type of turnsignals are you running? If you have the OEM ones with only 3 wires its much more complicated to have 3 brake lights. I've been curious if one could wire in 2 hydralic switches to have one just for the third brake light and the other for the stop and turn lights on the 1/4s.

Im running the oem 3 wires turning singals. but I dont understand what hydralic switchs you are taking about? thanks for such a quick replay Ed

[Ed Fleming]

Greg the diode ideal sounds great but what size do buy I was told there are all different sizes thanks Ed

[Cpt.Fred]

i wired mine as following:

using a switch like this:

if you use this setup, it' easy to hook up other stuff like third brake lights, but you have to have a third wire going directly to it and not going through the flashers.

only problem is, that you can either only use the signals and hazard flasher with ignition turned on or always, if you hook them up to a constant power source.

i had to use to flashers and 2 relais (diode?sorry my english is bad)) because you have to avoid constant light when using turn signals and brake at the same time.

i hope this helps!

p.s. he's talking about the brake light switch, i guess. those are hydraulic switches built into the brake line just before the master cyl. in the drawing above its the upper switch,

the one under it is your signal switch on the column.

Edited August 25, 2009 by Cpt.Fred

[Young Ed]

This is the device I was given plans to for making the OEM 3wire turnsignal unit work.

But I was thinking that it would be a lot simplier to just add a second hydralic brake light switch. The early 50s cars have them underneath by the rear axle. I did buy all the stuff for this fancy doodad except for the diodes but I haven't built it.

[busycoupe]

I don't know if this will help, but it is worth checking. My signals and brake lights were dim. I had a woman at a stop light tell me that I didn't have any brake lights. When I got home I checked them, they were working, but only dimly. I didn't find anything wrong with the wiring in the trunk, so I just left it alone. About a month later I changed the ignition switch in the dash. When I took out the old switch I discovered that the main power feed to the switch (which also powers the lights) had broken so that only a few strands of the wire were carrying current. I redid the connection, and suddenly all of my lights were brighter!

[Jim Yergin]

I used the schematic that Ed posted in my '41 P12 wagon using an original Mopar three wire turn switch. Works fine for me. I didn't use the diodes because I have the two bulb turn indicator/high beam indicator on my dash. I also don't have a middle trunk light. The wagon came standard with just a driver's side dual element tail light. The passenger side was optional and needed for turn signals. I added the passenger side light. I also colored the front parking light bulbs orange to make them more noticeable.

Jim Yergin

[greg g]

The hydraulic switch is the brake lamp switch, located in the brake lines in the vacinity of the master cylinder. It will have two connections one for power in and one for power out. The increase in line pressure when you apply the brakes makes the connection.

can't say what diode to buy, but if you go to radio shack they should be able to help you out, if you need one.

[Ed Fleming]

THANKS everyone Igoing out later to night to start some rewireing I will post what happens thanks once again .ED

[steveplym]

I did this on my car Ed. If you have an aftermarket turn signal switch it is really easy to do as you can wire the brake lights thru the switch. Here's a post from a few years ago when I did it.

Little follow up on this.

I have an aftermarket turn signal switch on my '47. It appears that it was installed in the 60's due to the appearing age of the switch. I traced the wiring coming from the switch on the column. Figured it had to be a 7 wire switch like the Foxton switch. I had pretty much figured I would have to buy another switch to achieve my desired result.

Then I got under the dash and found a wire wrapped around all the other wires coming from the turn signal switch. I was thinking this has to be the wire that is supposed to connect to the stop lamp switch. I checked this wire for voltage when ign and signal lights were on. None evident. So I hooked up power this wire. Both taillamps lit up on the bright side of the double filament. Proved that this is the wire that should be hooked up to the stop lamp.

I located the stop lamp switch and determined it was hooked up directly to the stop lamp in the trunk. I disconnected it from the switch and spliced a wire running from the stop lamp wire in the turn signal switch and the trunk stop lamp wire together into a male connector. Connected it to the stop lamp switch and all 3 lamps light in the rear with the brakes applied. All the signal lights work as well with brakes applied thanks to hooking them up thru the turn signal switch.

Took me 2 hours this evening to figure this out and about $2 worth of connectors/wires. This will really help letting other drivers who may follow too close that I am stopping. Gives me some peace of mind as well.

Edited August 26, 2009 by steveplym

[Young Ed]

So Steve if I'm reading this right you Y'd a wire off the brake light switch-one to the turn signals and one to the third brake light?

[steveplym]

So Steve if I'm reading this right you Y'd a wire off the brake light switch-one to the turn signals and one to the third brake light?

Yep, it lights the the quarter mounted lights thru the turn signal switch, plus it will turn off whatever side turn signal is on with the brakes depressed so you still have turn signals. Then the other wire runs straight to the center stop lamp. All three light up every time I press the brakes. I just put in a new heavy duty turn signal switch with hazards as well. It's great.

[Young Ed]

Got another question. I was discussing this with Dad. We have talked about this many times before and I always forget the reason he says it won't work. He has reminded me again. With only 3 wires how do you keep the parking lights from lighting up when you brake?

[paulmusiclover]

I've been following this thread with interest, as my stop light isn't working at all (have ordered a brake light switch to try that out) - and I just replaced the 3 wire one with a NOS 4 wire turn signal indicator.. I'm guessing the one that was in the car hasn't worked for years, as I don't think the flasher OR the actual turn signal handle works.

Unfortunately, I still don't have any turn lights! how would something like this work with a 4 wire system?

Paul

[Cpt.Fred]

Yep, it lights the the quarter mounted lights thru the turn signal switch, plus it will turn off whatever side turn signal is on with the brakes depressed so you still have turn signals. Then the other wire runs straight to the center stop lamp. All three light up every time I press the brakes. I just put in a new heavy duty turn signal switch with hazards as well. It's great.

that's what i meant. only with a 4 wire you have to put the relays in. works fine.

[Ed Fleming]

Hi guys ILL give you a update on the wiring I went with putting the diodes in the brake light wires it work no more feed back though the turning signal and all three brake lights work great . But are you ready for this all work great untill Iput on the head lights then I lost my turn signals .So Im still working on it thanks for the help .ED

[Young Ed]

Ed any follow up? I still need to get busy on adding signals of my own. And if I could do away with all the electric gagetry somehow and just have a simple 3 wire switch with 3 brake lights I'd be happy!

[Ed Fleming]

HI I still trying to work out one more promblem I HAVE THREE brake lites now and no feed back through the turning signals I put two diodes one in each brake light wire this stop the feed back of the turning signals but now when I PUT on the brakes my parking lights lite up Im thinking that the head light switch is were my problem lies the turning signals feed off the ignition but the brake lights feed off the light switch so IM still working on it ? IM going to try the second brake light wire .I will keep up dated .ED

[randroid]

Gents,

The cleanest and most simple system I've yet seen is the one most successfully used by several forum members, and that is to install a double filament bulb and run two independent circuits. Sure, you need to run two more wires from the dash both fore and aft, but diodes? Come on, our cars have been eligible for AARP for over a decade, so don't go trying to complicate what has a dubious outcome.

When I re-wire Pigiron's lights for turn signals I'll expect them to work correctly the first time and might become irritable if they don't because that would be my fault and not the fault of the system.

Input from those of you using a double filament system?

-Randy

[Jacqualine47]

Hey Ed,

Is there any chance that you can link us to somewhere we can pick up a DbDt relay, and maybe tell us what blades to the relay correspond to the internal coil and switches shown in the diagram you posted? That's the only component I've never had experience with before.

- Jacqualine