Conversion to LED (1157 tail lights & others)

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Conversion to LED (1157 tail lights & others)

Postby denizen44 » Fri Aug 18, 2017 6:13 pm

Didn't start looking for LEDs just for the fun of it... There was another reason.
It all started with a strange smell coming from under the dashboard.

Upon inspection I quickly homed in on the culprit: it was the brake switch.
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It overheated.
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Dayum...
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Hey no biggie, maybe it was old, or corroded... So I changed it. Twice! And used quality units.
But one day without warning the switch remained stuck on the ON position and drained the battery overnight.
It also got ridiculously hot. I had similar switch problems with my 1970 Sedan so I know this isn't just a single-specimen issue.

So I started doing some research.
My tail lights as many others, use the popular and inexpensive 1157 bulbs, with dual intensity.

Turns out the brake switch activates no less than TWELVE filaments...
Adding up the power draw from all the filaments with the help of the following chart,
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let's see what we get: (2.1 + 0.59) * 6 = 16.14 amps
for a total of (26.88 + 8.26) * 6 = 211 total watts! :o

No wonder the plastic can melt when it's very hot outside and/or the brake pedal is depressed for long periods, and especially if the contact zone inside the switch strayed ever so slightly, from being perfectly flat... Autopsy of an earlier switch revealed a non-flat contact surface causing tremendous heat.

I already have RE-DONE the wiring that leads to the switch in that area.. It's all 100% good and overdone.
Even used 12-gauge wire close to the switch instead of the standard 14 or 16, and there was no sign of overheating or resistance-inducing corrosion on any of the wires.

The source of heat is undoubtedly that contact point inside the switch, which just isn't large enough in my opinion.

In any case, I decided to switch to LED lights, because they draw so much less power.
Didn't seek a complete LED conversion at this time, just the tail lights.
Once a quality product is found, it should last some 10-12 years or so.
After research, I settled on the Katur brand, whose reviews are among the best.
Of course, there are other choices out there, but most are significantly more expensive.
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With the bulk package that contains 10 units, the cost is about 24$, or $2.40 ea.
Rather affordable yes, despite the cost of the right-side bulb being about 10 times less.
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33 diodes for each bulb, three of which are at the tip, behind a magnifying glass.
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Dual contacts. The quality of these seems quite adequate.
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Let's see now... according to the sheet below,

0.30 * 6 = 1.8 amps total;

wow :shock: nearly 10 times less power draw! :D
That brake switch sure will have an easy life from now on.

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Lumens = 900, instead of 400-ish. So more than twice as bright as the regular 1157s.
The all-around brightness makes really good use of a Lincoln's nice big reflectors.
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This is what they look like behind the lens.
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Using LEDs of RED color is widely and strongly recommended because if one uses white units, the result behind the lens will be pink-ish!
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The LEDs are always brighter than the incandescent bulbs.
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Also they light up much quicker, see video here:
https://vimeo.com/230222515

Side-by-side comparison (incandescent on the left side vs LED) here:
https://vimeo.com/230222981

With headlights ON:
https://vimeo.com/230223083


One of the main issues one faces when switching to LEDS, is the blinkers.
OEM blinkers on classic cars are designed to work under a given amount of current,
so these new low-current LED bulbs don't trigger it, especially when the headlights are on.

On the picture below, the top blinker is for Hazard only. But chances are your OEM blinker will still work with LEDS,
just like mine. The bottom blinker is for turn signals, and that's where things can get different.
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The OEM turn signal blinker on my setup (C) was one of those that only worked when the headlights were OFF.
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But I had a few extra units laying around which I tested, and the middle one (D0VB-13350-A)
just happened to operate flawlessly under all lighting situations... :D :D
Edit: This may very well be because there are still three incandescent bulbs on the turn signal circuit (i.e. front & sides)....

Many shops install resistor kits to fool the OEM blinkers into working with LEDs. But because my primary objective was to REDUCE the current in the system, this wasn't an option of course.
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Alternatively, I also ordered one of those widely recommended electronic flashers, whose operation is independent of the current load. That was my plan B if none of my blinkers had worked. I shall test the unit when it gets here, and post the results.
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Verdict: overall quite satisfied, would highly recommend the same brand. :smt033
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Last edited by denizen44 on Tue Sep 14, 2021 8:07 am, edited 17 times in total.
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Re: Conversion to 1157 LED tail lights

Postby denizen44 » Sat Aug 19, 2017 1:45 pm

Another quick note, there is another relay involved in turn signals,
whose function seems to be the blinking of the instrument panel lights.

Well that only works half of the time now.

Clearly a current-sensitive component.
Here is the relay in question (next to the similar emergency/hazard relay, which still works):

Image
Last edited by denizen44 on Thu Jul 04, 2019 12:11 pm, edited 5 times in total.
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Re: Conversion to 1157 LED tail lights

Postby Dan Szwarc » Sat Aug 19, 2017 6:36 pm

The interior lamps not flashing means you still don't have enough current. It's the bulb-out circuit that's tell you a bulb is out because it's designed for incandescents not LEDs.
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Re: Conversion to 1157 LED tail lights

Postby denizen44 » Sun Aug 20, 2017 7:04 am

But the strange part is, when using either turn signal, every exterior bulb flashes properly (all six bulbs, front and back)...
The semi-working "13A366?" relays cut off only the instrument panel lights.

➡️ Is the bulb-out system only supposed to freeze the instrument panel lights?
Last edited by denizen44 on Sun Aug 20, 2017 9:29 am, edited 1 time in total.
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Re: Conversion to 1157 LED tail lights

Postby Dan Szwarc » Sun Aug 20, 2017 9:17 am

It's telling you there is a bulb out by NOT flashing the inside.

They still work outside because that's safety. It's doing exactly as designed.
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Re: Conversion to 1157 LED tail lights

Postby denizen44 » Sun Aug 20, 2017 10:56 am

If the sole purpose of these relays is to control the behavior of the instrument panel lights, the latter can be restored by bypassing the relays.
I can live without the bulb-out warning system.

I will most likely install two standard (non current sensitive) 12V relays, and be done with it.
Last edited by denizen44 on Mon Sep 04, 2017 1:03 pm, edited 4 times in total.
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Re: Conversion to 1157 LED tail lights

Postby Dan Szwarc » Sun Aug 20, 2017 1:22 pm

This post has convinced me to put LEDs on my 66. I will report back sometime in a month or two when they arrive and I get a chance to work on the car.
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Re: Conversion to 1157 LED tail lights

Postby Dan Szwarc » Tue Aug 22, 2017 4:23 am

Rears are done.


Normal



Slo-mo


You can really see the transition speed difference in both videos. The LEDs truly switch from low to high and back while the bulbs slowly change their brightness up and down.

I need to paint the inside of my reflectors. The right side is actually brighter inside. The silvering is corroding on the left side.
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Re: Conversion to 1157 LED tail lights

Postby denizen44 » Tue Aug 22, 2017 5:32 am

Dan Szwarc wrote: I will report back sometime in a month or two when they arrive and I get a chance to work on the car.


Boy, time flies so fast! :wink:
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Re: Conversion to 1157 LED tail lights

Postby Dan Szwarc » Tue Aug 22, 2017 11:18 am

I was very excited they came so quickly, I couldn't hold my bulbs.
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Re: Conversion to 1157 LED tail lights

Postby denizen44 » Mon Sep 04, 2017 12:55 pm

The following explains how I restored the instrument panel lights. But I had to study the OEM system first.

When the turn signals operate, the sole purpose of these very atypical relays is to close the circuit of the instrument panel lights, controlling their ground connection and thus allowing them to light up, but ONLY if a given amount of current is passing through the system. This is by design, a crude bulb-out warning.
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In most 12V relays, a minimal amount of current is required to activate, despite large currents passing in the controlled circuit.
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But unlike typical relays, these "#13A366s" have a beefy activation circuit (the coil) that always lets a fair amount of current pass right through. Each relay submodel has its coil calibrated to the number of flashing bulbs in the vehicle.
So in any case, the introduction of low-current LEDS in the system, fools the beefy relays into being always OPEN, so even when the rest of the system flashes properly, the instrument panel lights never operate.
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In order to restore the instrument panel lights, one can try to bend some of the relay frame to lower its activation threshold, but that would require new calibrations if/when more LED bulbs are added.
So I decided to do away entirely with the bulb-out system.
From there, all that's needed(at least on a 70/71 LC) is to remove the relays, and give the panel lights a permanent ground connection.
This connection will not close any circuit until one of the TS switches are ON.
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The relays used to be bolted here and their frame served as ground.
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These 2 wires will now distribute the ground connection to the 2 wires of the formerly controlled circuit.
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Even if they could be jumped as-is, there is no real need to keep these relay sockets.
The wires inside can be slid out with a small screwdriver.
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These simple copper wafers will bridge the former activation wires.
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Heat shrunk insulation will slide over the new connections.
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All done.
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It works :D
and swapping-in more LEDS will not change that! :smt033
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Last edited by denizen44 on Mon Apr 02, 2018 9:15 pm, edited 5 times in total.
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Re: Conversion to 1157 LED tail lights

Postby CaptainB » Sun Sep 24, 2017 2:40 pm

Nice job , I wish you could tell me how to bypass the relay on a 66 . I've been banging my head on this for a while.
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Re: Conversion to 1157 LED tail lights

Postby denizen44 » Sun Sep 24, 2017 5:36 pm

Well, having the electrical schematics helps... :D

I'm pretty sure someone here has them for 67 *cough* DAN*cough*


Update:
After a few days using these Katur lights, I have come to the conclusion that they are just TOO BRIGHT for my taste. When the headlights are on in the evening, it almost looks like someone is always hitting the brake! Not the most dangerous thing of course, but not my favorite either...

So I have resumed my search for a set of bulbs closer to ~400-500 lumens, just like the original incandescent:
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When the nine new red #1157 types I ordered arrive in a few days, I'll make another update!
Couldn't find 1206 or 7014-based bulbs within the target lumen range, nonetheless I found others based on 5050s, 2835s(3528s), 4014s and 5630s so, a variety of different diode models.
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Also ordered:
-Reading & trunk lights (#1156, both white and warm white)
-Courtesy and map lights (#212, high-lumen white & ww)
-5 types of dash lights (#194)
-Back-up lights (#1076 Ba15d)
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Should be fun!
Last edited by denizen44 on Sat Sep 30, 2017 1:27 pm, edited 2 times in total.
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Re: Conversion to 1157 LED tail lights

Postby CaptainB » Mon Sep 25, 2017 1:39 pm

I can't find anyone who has on a 66, the above thread has all the schematics if you happen to get a minute to take a look. Would be appreciated if u have any ideas.
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Re: Conversion to 1157 LED tail lights

Postby Dan Szwarc » Mon Sep 25, 2017 2:03 pm

CaptainB wrote:I can't find anyone who has on a 66, the above thread has all the schematics if you happen to get a minute to take a look. Would be appreciated if u have any ideas.

I have LEDs on my 66 and the inside TS are completely dead. The outsides don't flash using the same flasher he bought. I ordered a 3-wire flasher that says works with any LED load.
I will work on the inside solution, but not until after the driving season ends.
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