Confused ground short in the rear light wiring?

[OUTFXD]

As I Have said before,  someone in the line of previous owners rewired Jacquiline Using Radio shack quality wiring,  but only used three colors.  This causes no end to head aches! 

 

Currently,  She seems to have developed a confused ground short.  Running lights work fine.  Break lights work fine.   If I turn on the turn signal,  BOTH rear lights flash,  regardless of which way I turn on the turn  signals. 

 

If I disconnect the black wire,  The turn signals work correctly, but I only have one break light. 

 

I am guessing I have a short somewhere back down the line. 

 

Ideas? Suggestions?  Number of a good Therapist? HALP!

 

P.S.  1946 Plymouth Special-Deluxe 

Edited January 26 by OUTFXD

[Ivan_B]

Was the car re-wired using the OEM diagram, or not? Are there just new wires or a completely new wiring scheme as well? Do you have the factory diagram available?

Edited January 26 by Ivan_B

[Sam Buchanan]

I suspect you have an aftermarket turn signal switch and it's wired incorrectly. Google Signal Stat and download a wiring diagram for the switch. It'll take some sleuthing to figure out which wires go where. Do you have colored wires like this coming out of the switch? 

 

Edited January 26 by Sam Buchanan

[OUTFXD]

49 minutes ago, Ivan_B said:

Was the car re-wired using the OEM diagram, or not? Are there just new wires or a completely new wiring scheme as well? Do you have the factory diagram available?

Oh heck no,  ALL wiring goes through the ignition circuit.  Turn the Ignition off.  no power to the Lights, horn, Brake lights... everything.

 

No clue what these guys thought they where doing.  a new harness is planned.  but reality keeps getting in the way. I am sure this is a safety  issue and I also have concerns about overloading the ignition switch.

Edited January 26 by OUTFXD

[OUTFXD]

16 minutes ago, Sam Buchanan said:

I suspect you have an aftermarket turn signal switch and it's wired incorrectly

 I went and looked at the switch.  its a Flashing-999  by the (I kid you not)  oo-Ray  lamp company.  it does indeed have colored wires. They disappear into the Jumble of loose wires  under the dash.  I think a new wiring harness just got bumped up. 

[Ivan_B]

Were the lights operating properly in the past? Did you make any changes such as new bulbs etc.? It is somewhat hard to guess what's going on without seeing your wiring. Do you have a multimeter to trace the wires from the switch down the road? I don't think there is a short, otherwise you would fry things and usually notice that right away. Could be that the switch is faulty, or something is not connected quite right.

Check the rear bulbs, specifically the turning light circuit. Left and Right wires should go their separate way, and might be connected to the same side bulbs on the front, then probably the switch or the flasher.

[Los_Control]

The only advice I have .... I suck at automotive wiring and facing wiring my truck.

I'm guessing that that this did work as it should at some point. Then you just found a issue so you are now investigating it.

 

So I'm not saying your wiring is correct, just that it did work .... and something has changed.

 

Bad grounds are brutal, a poorly grounded light socket will do all sorts of weird things ... it works when you do this, but when you add a brake pedal into it then it no longer works. .... Now it has too much current going through the wire and the poor ground just fails all together.

 

You know what I'm saying? .... It kinda works like it should, then it just stops working ..... could be several things but a bad ground is very possible.

Then if it worked before, you can look for a loose connection, a burned wire ..... trace it back as much as possible and see if you can find something wrong.

 

[Ivan_B]

46 minutes ago, Los_Control said:

Bad grounds are brutal, a poorly grounded light socket will do all sorts of weird things ...

Were you the one who dropped out of the electrician school? ? A bad ground light socket usually does not work. If we are talking about brake light with the regular dual filament bulb, there are two power wires going to it (parking light, brake light) and a single ground going out (to the body). There are not many things that can go wrong, really.

Wiring is not hard, really. You just need a little patience to look at the schematic (if you have one) and remember the main 3 rules: 1) you usually need + and - connected to make things work and if it doesn't, you probably have 2) no connection where there should be one, or 3) a connection where there should not be any

 

  

3 hours ago, OUTFXD said:

If I disconnect the black wire,  The turn signals work correctly, but I only have one break light. 

Based just on that, it make sense that if you disconnect the brake wire you have no brake lights. If the signals work correctly, however, it means that you are getting your signal going into the wrong bulb through the brake circuit, which does not make sense. What if you remove one of the bulbs, would the other still flash with the signal switch in both positions?

Edited January 27 by Ivan_B

[46BulldogDodge]

Check this recent thread by Tired Iron on the innards of a turn signal switch, should help you understand the wiring a bit.

 

Turn Signal switch inner workings

By Tired iron, January 18

[Sniper]

It is brake b r a k e not break

[OUTFXD]

8 minutes ago, Sniper said:

It is brake b r a k e not break

Sorry... I promisse that one day I will get it right.

[OUTFXD]

46 minutes ago, Ivan_B said:

Were the lights operating properly in the past? Did you make any changes such as new bulbs etc.? It is somewhat hard to guess what's going on without seeing your wiring. Do you have a multimeter to trace the wires from the switch down the road? I don't think there is a short, otherwise you would fry things and usually notice that right away. Could be that the switch is faulty, or something is not connected quite right.

Check the rear bulbs, specifically the turning light circuit. Left and Right wires should go their separate way, and might be connected to the same side bulbs on the front, then probably the switch or the flasher.

They used to work, With all the catywompus work that has gone into this car I am used to things failing.  I recall changing the pilot side turn signal bulb, Made sure it was 6v though. Multimeter, yes. Not real good with it. 

 

Both rear bulbs are fine though the pilot side doesnt seem to be grounding correctly. The pilot side bulb looses ground when it is fully inserted and locked into place. In the past i just turned it counter clockwise till it pushed against the lock.  Possibly a bad socket?

 

Looked around but cant find a replacement socket. Ours seems pretty Proprietary with the little spring clips that hook into the bodywork.  Anyone have a link to one? or a good parts number?

[Ivan_B]

7 minutes ago, OUTFXD said:

Sorry... I promisse that one day I will get it right.

I think that was meant for me, since I managed to type it 3 times right 2 times wrong in my previous message... Well, it's Friday, I am sorry ?

[OUTFXD]

41 minutes ago, Ivan_B said:

What if you remove one of the bulbs, would the other still flash with the signal switch in both positions?

Yes.  I know this because I had the flashers on while I was messing with the socket.

 

42 minutes ago, Ivan_B said:

does not make sense.

Welcome to MY world.

[Ivan_B]

2 minutes ago, OUTFXD said:

I recall changing the pilot side turn signal bulb, Made sure it was 6v though.

That could actually be source of the problem, depending upon the wiring. Those can be sitting parallel to the actual bulbs and if you've got a wrong combination of bulbs, "strange" things might happen. Are both of your pilot bulbs the same specs? What if you remove both of them, for testing?

You should be able to fix the original bulb socket (unless, of course, it is destroyed), if that is, indeed the issue. It is probably grounding to body (so a bad ground due to rust is a likely culprit).

[OUTFXD]

2 minutes ago, Ivan_B said:

Are both of your pilot bulbs the same specs? What if you remove both of them, for testing?

You should be able to fix the original bulb socket (unless, of course, it is destroyed), if that is, indeed the issue. It is probably grounding to body (so a bad ground due to rust is a likely culprit).

Not sure if the bulbs are the same,  I will look at that (and test) tomorrow. 

 

the old socket isnt rusted or corroded.  but it is... dirty.  I thought about soaking it overnight in vinegar.

 

Thanks for your input.  Gives me areas to look into.

[Ivan_B]

2 minutes ago, OUTFXD said:

I thought about soaking it overnight in vinegar.

Do you have a picture? If that's just dirt, it might be a better idea to clean it with some organic solvents (carb cleaner, gas, engine de-greaser), rather than using an acidic solution such as vinegar (technically, not good for the metal).

 

Is your turn signal switch the same as Tired iron's, posted above? In this case, we might also do some troubleshooting at the switch side (jumping wires) to test the after-the-switch circuit. A multi-meter is very useful for tracing wires. You will mainly use the continuity/diod setting. The one that beeps when both leads are connected.

 

[OUTFXD]

36 minutes ago, Ivan_B said:

, rather than using an acidic solution such as vinegar

Ahhh, Good point!

 

36 minutes ago, Ivan_B said:

Is your turn signal switch the same as Tired iron's

Nope. His is a factory installed unit.  Mine is an aftermarket unit attached to the steering collum with a hose clamp.

[kencombs]

Park/running lights work OK?  Do the front turn signals work correctly?   Brake lights only light up when brakes applied?  Be sure to check all four lamps and all eight filaments.

 

Losing ground when turned too far really sounds like a bulb and socket mismatch.  What bulb numbers are you using?  Take a look at the orientation of the bulb contacts relative to the locking pins and slots in the socket.

 

Troubleshooting others wiring is difficult at best, but the more info the more the guys can help.

[Sniper]

2 hours ago, Ivan_B said:

Were you the one who dropped out of the electrician school? ? A bad ground light socket usually does not work

 

A circuit will find a ground if there is any possibility.  When that happens wonky things occur.

 

In the case here, I suspect the turn signal switch more than anything else.  Simply because that is where the choices are made as to which light is being lit and when.

[Ivan_B]

You are right, and Los might actually be onto something. After all, after being in electrician school, he probably has more formal training than many of us, here ?

It could be that one side is feeding\grounding through the other. However, the TS stated that talking the bulbs out appears to have no effect and that all the lights appear to be working, besides this little problem with the turn signals. Could be a faulty switch, he might have to take a look at it, eventually, if other simpler troubleshooting proves fruitless.

Edited January 27 by Ivan_B

[greg g]

Well you have ro remember, rhe original harness was split between 2 circuits.  One for the 2 running lights (plus liscence plate lamp) and one for the single central brake li light.  When you add signal lights, this adds 2 more single circuits for right and left sockets.  The easiest way to address this is to add seperate lights to facilitate just the flashing lamps.  I added motorcycle signals to mine mounted to fabricated bracketsattached via a bumper bracket bolt.  I did this cuz I can't get my head around how the switch works especially through the brake light switch deal.  It's simple for switch to power the lamps through the flasher when just powering the signal, but when the brakes are on is it interrupting the ground to shut the lamp off or is something else going on?

Edited January 27 by greg g

[Sniper]

Here's a graphic that may help understand how the turn signal switch works

 

 

 

[Ivan_B]

43 minutes ago, Sniper said:

Here's a graphic that may help understand how the turn signal switch works

That looks like the OEM system, like what Tired iron has, doesn't it? I think OUTFXD is using some kind of aftermarket setup.

 

1 hour ago, greg g said:

but when the brakes are on is it interrupting the ground to shut the lamp off or is something else going on?

The above diagram is using only the brake circuit, on the back. So you either have the light bulb connected through the brake switch (steady light if the pedal is down) or to the flasher if the switch is activated to either position. Nothing is done to the ground, the bulbs are always grounded to the body where the lamp bracket is. A very elegant and simple system, actually. I had to use 4 relays in my "custom" setup because I did not have this type of switch\wiring and did not want to use the aftermarket ones or mess-up the factory harness ?

[OUTFXD]

A confused ground happens thusly (puts on his high school education ribon)

 

Turn on the left turn signal,  this sends power down the circuit to the light bulb.  Red line 

 

but the light bulb has poor/no ground.   The electricity has to go somewhere.  So looking for a ground,  it follows the other circuit connected to that contact.

 

It travels back through the Brake light circuit (Orange line) and finds ground through the other bulb, powering the bulb.

 

All good? okay, Ill go back to being stupid again.