57 Imperial - Tail Light Wiring
imperial2100
Posted 2018-08-02 9:54 PM (#567688)
Subject: 57 Imperial - Tail Light Wiring


Veteran

Posts: 169
1002525
Location: Columbus, OH
Have been replacing the old tail light bulbs with new LEDs and having to replace sockets because the original one on driver side broke off one too many tabs to hold it in, and the passenger side is a modern replacement socket that doesn't place the bulb deep enough into the plastic housing causing the passenger side to be dim.

Anyway, in doing this, I seem to have possibly screwed something up with this simple wiring. Let me first describe the wiring for this model car - there's only 1 light on each side, that's it! The light is the compound type that has two wires to light up half or both sides of the bulb.

Now, when the key is turned to the on position, the tail lights light up in the lower light mode. This means one of the two wires is completing the circuit to light up half of the lights, but it's not supposed to light up at all during day-time operation.

When I hit the brakes, both lines are in circuit because it lights up nice and bright as it should. (so this is working I assume)

When I turn the headlights on, both tail lights light up on the bright setting, just as if I was pressing the brake pedal. And if I press the brake pedal, it cannot get any brighter as both wires are in circuit already.

Turn signals are working causing the lights to blink on/off or bright/dim depending on if headlights are on.

Is there some simple fix or mistake that I'm missing here? Or do I have a gremlin I just need to begin tracking down?

Edited by imperial2100 2018-08-02 9:55 PM
Top of the page Bottom of the page
KcImperial
Posted 2018-08-03 12:40 AM (#567706 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert

Posts: 2490
2000100100100100252525
Location: Kansas City, KS
not a wiring expert by any means and certainly know zero about LED's or what you may have already altered
I did have similar troubles on one of mine - two things could be a problem in general with these Imperial tail lights
1) they ground through the bulb housing. will cause gremlins if not seated properly or dirty/corroded
2) everything is wired through the light switch on the dash, mine was bad

fyi - 1957 is a one year, Imperial only switch if you ever need to replace it
Top of the page Bottom of the page
ttotired
Posted 2018-08-03 4:34 PM (#567736 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert 5K+

Posts: 8443
50002000100010010010010025
Location: Perth Australia
I think you trouble is starting with the flasher unit. Try unplugging it and see if the first problem goes away, if so source an LED compatible one

As for the second and third ones, it could be a faulty earth (makes the brake feed through the tail or vis versa) or even crappy LEDs

Thing to remember with LEDs is they take virtually nothing to light up and what was a design benefit with bulbs can be a problem with LEDs

It sounds like you have some fun times ahead of you tracking it out, or save some time and put bulbs back in and use that time to have a beer or 2

Top of the page Bottom of the page
imperial2100
Posted 2018-08-03 5:22 PM (#567744 - in reply to #567736)
Subject: Re: 57 Imperial - Tail Light Wiring


Veteran

Posts: 169
1002525
Location: Columbus, OH
ttotired - 2018-08-03 5:34 PM

It sounds like you have some fun times ahead of you tracking it out, or save some time and put bulbs back in and use that time to have a beer or 2

I hadn't thought of that. I'll stick the bulbs back in and see if the problem goes away, but I didn't think current draw played any part in the function of the tail lights on these older cars. I know in modern cars there are sensors at play that will indicate you have lights out if you don't put in-line resistors with the LEDs. What part of the older cars is built around the current draw? The turn signal flasher? The flasher seems to be working great with the LEDs right now though.
Top of the page Bottom of the page
ttotired
Posted 2018-08-03 7:36 PM (#567751 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert 5K+

Posts: 8443
50002000100010010010010025
Location: Perth Australia
Some cars (I cant remember exactly which ones) send a back feed through the dash indicators, they earth through the opposite side. Kind of hard to explain

The other problem with LEDs is because they don't draw hardly anything, the self cleaning feature of current flowing through contacts is lost (as the contacts get dirty, they arc, cleaning the contacts)

This feature also gets lost when relays are fitted. Removing the load saves contact wear, but can mean switch failure due to oxidisation which requires the manual cleaning of the switch.

The act of turning the switch on and off is not normally enough to clean the contacts.

I was at one stage quite excited by LEDs, but since their popularity about 10 or so years ago, I have had to change out more lights than if it actually had good quality incandescent bulbs.

Think about it, most of the bulbs that were in your car were most likely as old as your car

Top of the page Bottom of the page
imperial2100
Posted 2018-08-04 10:19 PM (#567815 - in reply to #567688)
Subject: RE: 57 Imperial - Tail Light Wiring


Veteran

Posts: 169
1002525
Location: Columbus, OH
Well switching back to the original bulbs worked. The lights stay off when the car is running with headlights off and they turn on low when you turn on the headlights. Then turn on high when you press the brake.

Really strange they function this way, I'll have to track down a schematic because I'm really interested to see how they wired this up as it doesn't make any sense to me right now. The LEDs are connected and function the same as the bulbs, except that they do not draw much power in comparison to the bulbs, so what is in this circuit that depends on current draw for it to function I wonder.
Top of the page Bottom of the page
56D500boy
Posted 2018-08-05 12:34 AM (#567816 - in reply to #567815)
Subject: RE: 57 Imperial - Tail Light Wiring



Expert 5K+

Posts: 9855
5000200020005001001001002525
Location: Lower Mainland BC
Not sure what the problem is but I will share that when I converted my taillights to LED bulbs, I had to get a signal flasher that was electronic and not mechanical (based on bi-metal springs,etc). Everything has worked since then for me.

As for the wiring, if you have the 57 Chrysler Service manual, I think you will find the wiring diagram you need on page 401.

I didn't have it but I went to:

http://www.mymopar.com/index.php?pid=109

And then I downloaded the 57 Chrysler and Imperial service manual. After a bit of poking around, I found page 401 on page 403 of the 458 page pdf.

Hope it helps:





(1957ChryslerLightingAndTurnSignalWiring.jpg)



Attachments
----------------
Attachments 1957ChryslerLightingAndTurnSignalWiring.jpg (225KB - 160 downloads)
Top of the page Bottom of the page
hemidenis
Posted 2018-08-05 9:12 AM (#567828 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert

Posts: 3887
20001000500100100100252525
Location: Northen Virginia
Like D500 said, you can not replace the rear light or the front with LED, or you need to replace the whole turn signal system. Don can tell you more about the Imperial electrical system nightmare.

You can probably engineering a system using a micro-controller loaded with a program that recognize the movement (left or right) of the switch and then do the blinking electronically. OR back to the regular bulbs..

Eventually I'm going to do the electronic conversion to my Imperial, so I could also add 4-way flasher...







Edited by hemidenis 2018-08-05 9:14 AM
Top of the page Bottom of the page
56D500boy
Posted 2018-08-05 11:15 AM (#567831 - in reply to #567828)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert 5K+

Posts: 9855
5000200020005001001001002525
Location: Lower Mainland BC
hemidenis - 2018-08-05 9:12 AM
Like D500 said, you can not replace the rear light or the front with LED, or you need to replace the whole turn signal system.


If you are referring to me (56D500boy), I didn't say that. I only said that I had to install an electronic flasher in my 56 Dodge when I added LED taillight bulbs.

REFERENCE: http://www.forwardlook.net/forums/forums/thread-view.asp?tid=64943&...

In a 56 Dodge, the signal light and brake light functions for the second (active) filament in the 1157 bulb are controlled mechanically by the signal light switch, no electronic relay like in the Imperial.


Top of the page Bottom of the page
ttotired
Posted 2018-08-05 6:05 PM (#567851 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert 5K+

Posts: 8443
50002000100010010010010025
Location: Perth Australia
You may not find anything that's going to be "current dependant" like you think

As I said, you need to change the flasher unit and if that's not the culprit, you need to trace out from there

It could be the brake switch letting a tiny bit of current through, or dirt on it letting it through or even dirt or moisture on a junction plug, it
could be anything

Although the electricity in a car generally wont kill you and you normally don't even feel it (you can get booted off some circuits) it behaves exactly the same
as high voltage and will track through dirt and water. Because incandescent light bulbs need X amount of current, the amount tracking through the dirt
isn't enough, but its can be plenty for an LED.

This is why I normally do not use an LED test lamp because enough current can flow through a cracked wire to make them light up

Top of the page Bottom of the page
imperial2100
Posted 2018-08-05 6:50 PM (#567855 - in reply to #567851)
Subject: Re: 57 Imperial - Tail Light Wiring


Veteran

Posts: 169
1002525
Location: Columbus, OH
ttotired - 2018-08-05 7:05 PM

It could be the brake switch letting a tiny bit of current through, or dirt on it letting it through or even dirt or moisture on a junction plug, it
could be anything

Although the electricity in a car generally wont kill you and you normally don't even feel it (you can get booted off some circuits) it behaves exactly the same
as high voltage and will track through dirt and water. Because incandescent light bulbs need X amount of current, the amount tracking through the dirt
isn't enough, but its can be plenty for an LED.


This is actually a very good explanation. As everything seems to function fine with the LEDs except they are lighting up at all times when the ignition is on. I'll put a volt meter on it to see if any voltage is making it to the sockets. If something is getting through (enough to power an LED) then I should be able to measure it.
Top of the page Bottom of the page
imperial2100
Posted 2018-08-05 7:28 PM (#567858 - in reply to #567855)
Subject: Re: 57 Imperial - Tail Light Wiring


Veteran

Posts: 169
1002525
Location: Columbus, OH
imperial2100 - 2018-08-05 7:50 PM

ttotired - 2018-08-05 7:05 PM

It could be the brake switch letting a tiny bit of current through, or dirt on it letting it through or even dirt or moisture on a junction plug, it
could be anything

Although the electricity in a car generally wont kill you and you normally don't even feel it (you can get booted off some circuits) it behaves exactly the same
as high voltage and will track through dirt and water. Because incandescent light bulbs need X amount of current, the amount tracking through the dirt
isn't enough, but its can be plenty for an LED.


This is actually a very good explanation. As everything seems to function fine with the LEDs except they are lighting up at all times when the ignition is on. I'll put a volt meter on it to see if any voltage is making it to the sockets. If something is getting through (enough to power an LED) then I should be able to measure it.

You were right, something is bleeding 11v over the two points on the socket. So not with the ground and a single wire, but between the two wires, the one that should only be on when the headlights are on and the other used for turn signal/brakes.
Top of the page Bottom of the page
imperial2100
Posted 2018-08-05 9:36 PM (#567867 - in reply to #567688)
Subject: RE: 57 Imperial - Tail Light Wiring


Veteran

Posts: 169
1002525
Location: Columbus, OH
Well after some research and help from an EE relative, I was reminded that an LED is a diode (the D obviously) which I had forgotten. So the fact that an LED is a diode and will only allow current flow in one direction means if it was an LED wired in directly to the pins on the base, it would never allow current to flow from pin 1 to pin 2, only from one of the pins to the ground/base.

So the fact that the LED works when current is flowing from pin 1 to pin 2 means it's not wired directly in and there's some other circuitry mixed in here. I have two 1157 style LED lights, one is a cheap design and the other was much more expensive. The cheap one has the LED's wired directly in line, so apply a 9v battery for instance to the two pins does nothing. The expensive LED was expensive because it has additional circuitry for whatever reason and will light up when applying a 9v battery to the two pins. This is why the nice expensive LED's I bought are always lighting - they have extra circuitry internally and are not behaving like a set of diodes.

The incandescent bulbs also light up one of their filaments, but only if there's enough current to do so, which never happens in the car. The bleed over is never enough to make the filament glow and instead the filament simply burns off the extra electricity - likely at a light level you could never see with your eyes.

So the cheap LED lights work in the car, just like the incandescent bulbs do, but not because they are wired the same, but because they are wired different because they are diodes.

The expensive LED lights do not work in the car, not because they are wired different but because they are wired the same, because they are not acting like diodes. Weird, but it all comes down to the amps needed to run a filament vs an LED... the filament is burning it off with no light while the LED is able to glow with that minor bleed over.

Or I could be completely wrong on all this and someone will correct me. Right now though I have the cheaper style LEDs in the car and they are working perfectly, just like the old bulbs.
Top of the page Bottom of the page
hemidenis
Posted 2018-08-05 9:47 PM (#567870 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert

Posts: 3887
20001000500100100100252525
Location: Northen Virginia
obviously you can not just replace the flasher for an electronic in the Imperial, since is an integrate unit with 10 pins.

56 had a regular 3 pin flasher.

56D500boy, I thought you implied it in your comment, looking at the Imperial electrical system, I didn't know that i'm the only one seen it.

The LED will never replace a bulb in the original electric system because the way the Flasher works. The flasher design is based in high consumption of electricity that a LED will never provide. The flasher does not "see" the LED and for the flasher it is not bulb there.
Top of the page Bottom of the page
imperial2100
Posted 2018-08-05 9:59 PM (#567872 - in reply to #567870)
Subject: Re: 57 Imperial - Tail Light Wiring


Veteran

Posts: 169
1002525
Location: Columbus, OH
hemidenis - 2018-08-05 10:47 PM

The LED will never replace a bulb in the original electric system because the way the Flasher works. The flasher design is based in high consumption of electricity that a LED will never provide. The flasher does not "see" the LED and for the flasher it is not bulb there.

The LED is already replaced and working in the original system. The flashers are working fine for the turn signals, they are running at the same frequency as the old bulbs did. This could be due to the fact that the front lights are still incandescent, won't know till I try replacing them. I'll give that shot and see if the turn signals still function.

I don't think I would ever try to replace that switcher relay in the car, it's actually got 11 pins on it and I'm sure it's tucked away somewhere that is not easy to work on.
Top of the page Bottom of the page
KcImperial
Posted 2018-08-05 11:34 PM (#567877 - in reply to #567872)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert

Posts: 2490
2000100100100100252525
Location: Kansas City, KS
imperial2100 - 2018-08-05 8:59 PM
I don't think I would ever try to replace that switcher relay in the car, it's actually got 11 pins on it and I'm sure it's tucked away somewhere that is not easy to work on.

Here's what it looks like. It's located behind the driver side kick panel



(57Imperial.jpg)



Attachments
----------------
Attachments 57Imperial.jpg (93KB - 169 downloads)
Top of the page Bottom of the page
KcImperial
Posted 2018-08-05 11:36 PM (#567879 - in reply to #567877)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert

Posts: 2490
2000100100100100252525
Location: Kansas City, KS
and here's a full dash pic if you ever need inspiration for messing with an Imperial wiring harness



(dash.jpg)



Attachments
----------------
Attachments dash.jpg (159KB - 167 downloads)
Top of the page Bottom of the page
imperial2100
Posted 2018-08-05 11:41 PM (#567881 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring


Veteran

Posts: 169
1002525
Location: Columbus, OH
Thanks KC. I'm going to try my best to never go that deep into my Imperial if I can help it. I do think I might try pulling out the gauges at some point to try and put some brighter bulbs in, but I'm going to wait a little longer on that one
Top of the page Bottom of the page
KcImperial
Posted 2018-08-05 11:52 PM (#567882 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert

Posts: 2490
2000100100100100252525
Location: Kansas City, KS
The gauges bolt in from the backside of the dash.
Phil has a page on his website where he changed out the speedometer while the dash was still in the car
I think it's about a toss up if that was actually easier than just pulling the whole dash
Top of the page Bottom of the page
hemidenis
Posted 2018-08-06 3:39 PM (#567930 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert

Posts: 3887
20001000500100100100252525
Location: Northen Virginia
what a nightmare Don, looking at this paying $600 for a new whole electrical system doesn't seem a lot.

The flasher is working because the original bulb in the front, and usually does not work with only one, but several LED could get close to a Bulb consumption, just have to try.
Top of the page Bottom of the page
ttotired
Posted 2018-08-06 4:19 PM (#567933 - in reply to #567688)
Subject: Re: 57 Imperial - Tail Light Wiring



Expert 5K+

Posts: 8443
50002000100010010010010025
Location: Perth Australia
If your really hell bent on the LEDs (and it looks like you are) then get the load resistors and fit them. Remember, they get quite hot and can (do) melt plastic

I wouldn't mess with that flasher either (unless it crapped itself) but you will find once you change the fronts out, it will no longer flash, hence the resistors

That flasher could be changed out, but (without looking at a schematic) I think it would require 2 "normal" flasher units, but I am only guessing as I havnt looked into it



Top of the page Bottom of the page