Patrick - LED Taillight problems

[kevins2]

Originally Posted by DanEC

As a follow up - I installed a set of the Walmart Pilot 1157 LEDs in my old Corvette today. I now realize that the 3 LED groups on the top or end of the bulbs are the ones that light up for brakes and turn signals. the LEDs around the bulb barrel are the ones that illuminate for tail lights. That works great with bullet type tailights like the Corvette or the round lights if used on the rear of a Cobra. My ERA has rectangular lights on the rear which means the LEDs for the brake and turn signal are pointing up into the top of the light housing - rather than directly to the rear - thus the reason they didn't seem especially brighter on brakes or flashers. On my Corvette, since they are pointing out the rear, they are very bright.

For a Cobra replica with the round tail lights these are a very cost effective way to get LED tail lights - costing around $30 for 4 bulbs. I doubt they can be distinguished in brightness from the Superbrightleds which cost roughly $100 for 4 bulbs.

For rectangular tail lights they are not quite as good but OK - at least on brake and turn signal brightness.

The Superbrights work differently, all 45 LEDs are dual intensity and light up for both taillight and brake/turn signals.

[DanEC]

Originally Posted by kevins2

The Superbrights work differently, all 45 LEDs are dual intensity and light up for both taillight and brake/turn signals.

Kevin - I thought I remembered they did from testing with a battery charger but I wasn't sure.

[Tom Wells]

Well, I tried to stay out of this one...

But after I saw some success with the not so expensive 1157 red LED lights from Pilot, I went to Walmart to buy some. They didn't have any. So I went to Autozone and got two packages of two, as I have the twin bullet-shaped lights on each side. Naturally they were $20/pair instead of $15/pair

My lights are wired so that all four of them come on for the parking and stop lights, dim for the former, bright for the latter. Both the lights on the same side blink (bright) for the turn signal, alternating bright/dim when the headlights are on and bright/off when the lights are off.

I put in two of the LED lights and all was fine: both sides still did the job they had been doing with the incandescents. So I put the other two in and the fun started.

If I put the first two (good) LED units on one side and the second pair in the other side, the good side blinked properly. The other side, when the turn signal tried to activate it - made the two lights with the BAD LED lights alternate between bright and dim at the same time as the good side indicated a turn properly with bright/off. Picture a funky 4-way flasher with the pair on one side blinking on/off and the pair on the other side side blinking bright/dim.

Rearranging the bulbs into other sockets affected the pattern by switching it from one side to the other, but the GOOD side always worked fine - the BAD side made the other side go bright/dim instead of on/off.

I know, you really do need to see the movie

Conclusion (reinforced by putting good bulbs in all sockets): the BAD LED bulbs had some sort of anomaly, probably a short, causing the odd behavior.

Solution: take the BAD pair back to Autozone and swap for a good pair.

Takeaway: not all LED bulbs are equal, even the same make, model and serial number.

If you don't understand this, I don't blame you!

Tom

[DanEC]

Originally Posted by Tom Wells

Well, I tried to stay out of this one...

Takeaway: not all LED bulbs are equal, even the same make, model and serial number.

If you don't understand this, I don't blame you!

Tom

I understand. After my initial believed success in post #78, I later re-tested and realized I didn't try the flashers with my parking lights and headlights turned off. When I tried my turn signals with the parking lights off, all 4 lights flashed. Same for the other turn signal. Choice was to always drive with my lights on (which I usually do) or go back to the 2357 bulbs. Flashers and brakes work fine with the parking lights and/or headlights on. I re-installed the 2357 bulbs. I think my problems are from the flasher unit. But ERA uses a pretty specific flasher unit and I don't know what would be appropriate to try as a substitute. I think the extra load with the lights on allows the flasher to function correctly somehow even though they are separate circuits. Basically, I'm back to surrender - 'no mas'.

[patrickt]

Originally Posted by DanEC

But ERA uses a pretty specific flasher unit and I don't know what would be appropriate to try as a substitute. I think the extra load with the lights on allows the flasher to function correctly somehow even though they are separate circuits. Basically, I'm back to surrender - 'no mas'.

There is nothing unique about the ERA wiring schematic. It's very, very straightforward. The "load" that is needed to trip the old fashioned mechanical flasher unit which, in turn, repeatedly interrupts the current to the trailer relay, comes from the front bulbs. So, you should only use old fashioned filament light bulbs up front. The trailer relay can be temperamental and it's a little tricky to test outside of the car. So, your best bet, when replacing the trailer relay, is to install the three inputs to the relay, while it just hangs down right there in the driver's leg area, and then "test wire" your lights with short, 1 foot long runs to your lights, that you have removed, and that are now just sitting on the driver's floor board. Just make sure you have a clean temporary ground wire running to those lights as well (for temporary ground wires, I always just run a long alligator clip wire directly to the negative battery terminal). Let me say it again, there are only three wires going in to the trailer relay, and two wires going out, and only the brake lights and turn signals are involved in this circuit. The parking lights have nothing to do with this. The circuit is ridiculously easy to test if you do it this way -- and testing it this way will "red flag" a wiring problem between the trailer relay and the back of the car. A nice, high-output, trailer relay, suitable for use in the ERA, can be bought off Amazon or the 'net. Look for 3-2, and "Heavy Duty." Here you go, this one would do just fine:

Ultra-Fab Heavy Duty Relay 3-2 Tail Light Converter 6-amp 36-947001 by Ultra-fab Products, Inc. for $10.97 : Rural King

[DanEC]

I feel I've invested more time in this endevor than it's worth. I've polished up the inside of my reflectors, added foil over the open areas on top and installed brighter flashing 2357 bulbs and it looks pretty good. It's not going to blind people sitting behind me a a stop light but they will see it unless they aren't paying attention texting or something - at which time it probably won't matter anyway.

I'm still thinking a flasher issue - that's what most LED bulb problems come down to. But maybe it is the trailer relay. My issues are just too wierd:

Install LED bulb in one front parking light:

- Parking lights off and turn signal on - all lights flash including license plate light.

- Parking light on and turn signal on - nothing happens on side with LED bulb.

- Tried both sides and tried two different LED bulbs and same results.

Install LED bulbs in rear only:

- Parking lights off and turn signal on - all 4 lights flash including license plate light.

- Parking lights on and turn signal for right or left side - turn signals and brake lights flash normally at front and rear.

Completely opposite results with parking lights on depending which end of the car I install the LEDs. Too wierd. I do have a couple extra trailer relay units so who knows - if I get to needing something to do.

[patrickt]

Yes, that's bizarre. But what I would like to see is if you had the exact same results when the lights are just temporarily wired one foot away from the relay itself, all hanging right there in front of the driver's seat, thereby eliminating all wiring issues from that point to the back of the car. There's a mistake, or a malfunctioning component, somewhere... there has to be.

[Tom Wells]

Dan,

My problem exactly: lights on, everything works as it is supposed to. Lights off - 4-way flasher effect.

I have an E-M which has to be wired similarly but probably not the same(?) as your ERA - same behavior.

I have a "heavy duty" flasher so tomorrow will try to find a "light duty" flasher

Tom

[DanEC]

Tom - I will be curious to hear what happens with the flasher experiment.

Patrick - maybe in warmer weather.

[Xack]

Originally Posted by DanEC

I feel I've invested more time in this endevor than it's worth. I've polished up the inside of my reflectors, added foil over the open areas on top and installed brighter flashing 2357 bulbs and it looks pretty good. It's not going to blind people sitting behind me a a stop light but they will see it unless they aren't paying attention texting or something - at which time it probably won't matter anyway.

I'm still thinking a flasher issue - that's what most LED bulb problems come down to. But maybe it is the trailer relay. My issues are just too wierd:

Install LED bulb in one front parking light:

- Parking lights off and turn signal on - all lights flash including license plate light.

- Parking light on and turn signal on - nothing happens on side with LED bulb.

- Tried both sides and tried two different LED bulbs and same results.

Install LED bulbs in rear only:

- Parking lights off and turn signal on - all 4 lights flash including license plate light.

- Parking lights on and turn signal for right or left side - turn signals and brake lights flash normally at front and rear.

Completely opposite results with parking lights on depending which end of the car I install the LEDs. Too wierd. I do have a couple extra trailer relay units so who knows - if I get to needing something to do.

Dan,
It seems you have feedback which has enough difference in potential to drive your lights on. My initial thought is regarding your grounds. You stated that should not be an issue. That is easy enough to measure.

I'm curious if you have similar issues if you just take one of the incandescent bulbs out and do not have any LED bulbs in your circuit. This may help you eliminate issues that do not depend on the LED question. LED's have low current and 12 volts can be measured at the hot side of the bulb when on. This is similar to open circuit condition.

[DanEC]

Originally Posted by Xack

Dan,
It seems you have feedback which has enough difference in potential to drive your lights on. My initial thought is regarding your grounds. You stated that should not be an issue. That is easy enough to measure.

I'm curious if you have similar issues if you just take one of the incandescent bulbs out and do not have any LED bulbs in your circuit. This may help you eliminate issues that do not depend on the LED question. LED's have low current and 12 volts can be measured at the hot side of the bulb when on. This is similar to open circuit condition.

I think it is some sort of cross-talk issue through the flasher, turn signal or trailer relay unit. That it's picking up the license plate lamp and flashing it is also wierd. About the only thing these 3 cirucuits have in common is the battery and grounding through the frame to the drivetrain.

So, you are suggesting to remove one of the four 1157 bulbs and try the turn signals and brakes to see what I have on the remaining 3 bulbs? Or jumper the power and ground at the removed bulb socket?

[Tom Wells]

I'm convinced it's the LEDs.

I tried to find an LED compatible electronic flasher locally yesterday and came back with one labelled EP-35. When I removed the thermal flasher (550) that was in there and replaced it with the electronic one, nothing happened. No flashing, no nothing with the lights on or off.

There were only a few combinations that seemed to work while keeping the 550 flasher in place: putting the original 1157 bulbs in all four sockets; or just the lower sockets with the Pilot LEDs in the uppers, or some no-name LEDs I got from Amazon in the same two lower sockets while the upper sockets were occupied by the Pilots.

For the time being the latter will stay even though the lower LEDs don't flash - well, maybe ever so slightly. The all-LED combo seems much brighter than the 1157s which is what I was after all along.

I do think I'll try to find a different electronic, LED-compatible flasher at some point.

Wearily,

Tom

[Xack]

Originally Posted by DanEC

I think it is some sort of cross-talk issue through the flasher, turn signal or trailer relay unit. That it's picking up the license plate lamp and flashing it is also wierd. About the only thing these 3 cirucuits have in common is the battery and grounding through the frame to the drivetrain.

So, you are suggesting to remove one of the four 1157 bulbs and try the turn signals and brakes to see what I have on the remaining 3 bulbs? Or jumper the power and ground at the removed bulb socket?

If you have the system with just incandescent bulbs, No LED's at all. Take a bulb out as if it's "blown" and see how the system operates. Will it do anything strange? No jumper anything at all.

The unplugging will help you see what acts normal when you isolate parts of your system by pulling bulbs out... However, your blinker circuits depends on a load for the flasher to work. When you take out the bulb, I would expect that side to not blink properly. The other side should work OK. This pulling the marker light bulb will check behavior for the marker light circuit only. Now, having said that, it may show something misbehaving and you can do these bulbs to try and isolate the problem.

I would suggest after all that and see if strangeness persists, to connect the ground on the offending bulbs to the battery ground or as close to it as possible. You can just put your VOM on ground at bulb and ground at battery to see if it goes up by any measure from 0 Volts to + something to drive a light on. Jumping the ground at the bulb should allow you to isolate issues surrounding grounding.

[Xack]

I had a similar thing with 2 incandescent bulbs in my dash linked to the individual circuits for showing turn signals. Also when I turned on the lights you could actually trace the lights coming on in a wave across the panel. The opposite side bulb would light dimly as the main bulb was bright. This was true for both bulbs. I had a daisy chain power to the dash gauges and bulbs and a similar approach to the grounds on each device. All I did was run each device ground wire to a common ground under the dash. That cured the problem. The lights on the dash are noticeably brighter.

[DanEC]

I think I well past the point of being a pest with this thread so I guess I may as well go for broke.

To better understand the running (parking) light circuit and the signal circuit I sketched them from ERAs wiring diagram.



When I install LED in both rear lights the following happens:

Parking Lights - OFF, but Ignition ON

Turn Signal turned on.

All four corner lights flash and the license plate light. I can see that on the side the turn signal is turned on - the parking light and flasher led elements are ALL flashing. On the opposite side, ONLY the parking light led elements are flashing (not the turn signal ones).

Not sure on the front but I think both filiments on the side with the turn signal on are flashing and on the opposite side the parking light filiment is flashing.

So . . . the puzzle is how is power getting to the parking light circuit with the parking lights off? The parking light and turn signal light circuits are pretty separate and I can't see where they could be cross-talking by a relay or something.

Parking lights (and license light) are all tied together and come off of the #6 fuse which is fed by the light switch and in turn fed from the ignition switch.

As far as I can understand the turn signals draw power from the #4 fuse to the flasher unit and then to the turn signal switch.

When I tried to test LED bulbs for continuity I got nothing so they are kind of like relays and have to be fed power. In my not-electical circuit oriented mind it seems like the bulb internals must be leaking power from the turn signal cirucit to the parking light circuit and back feeding it.

I did try to remove a sigle bulb at a time to see what happened but the results were what is expected. Side with bulb removed didn't flash but the other side did.

Thoughts Patrick?

Edit: I forgot to mention that when I turned the parking lights ON with LEDs in place - all lights and signals worked 100% correctly.

[patrickt]

First step, is to get two ten foot long wires, of typical lamp cord gauge, with alligator clips securely on the end of each. Clamp one end of each to the negative terminal of your battery and the other end of each to the black wires directly at the connection to each of your rear light assemblies on both sides of the car. Yes, I know, you're 100% sure your grounds back there are absolutely pristine, but just do it anyway, and re-test. We will leave those ground wires in place throughout the diagnostics.

[Xack]

LED's are diodes. They emit light when forward biased. They don't work or conduct when reversed biased. In other words, put in backwards they don't work. You can see if they are OK, by using a VOM with a diode check. Normally this is the diode symbol. The VOM will beep when red is on the Annode or the back of the triangle and the black is on the cathode or the line across the tip of the triangle. If you reverse the connection then nothing will happen.

A diode is a one way valve. It will conduct in one direction. You reverse the connection and it acts as a switch turned off. They are pretty simple and usually use much less current to illuminate vs. incandescent bulbs.

[DanEC]

I'll have to check my meter to see if it has that feature. Thanks.

[patrickt]

Originally Posted by DanEC

So . . . the puzzle is how is power getting to the parking light circuit with the parking lights off? The parking light and turn signal light circuits are pretty separate and I can't see where they could be cross-talking by a relay or something.

Thoughts Patrick?

The parking light filament, and the turn signal/brake filament, are indeed separate. However, they have a common ground. If the connection to the common connector is good, but from the common connector to the ground is faulty, it will back feed right up the other filament. Follow my previous instructions by running the two ten foot alligator clip lines and retest. If everything is exactly the same, then do the exact same thing with the two front bulbs using two more eight foot alligator clip lines, then retest (yes, you will have four temporary ground lines draped over the car).

[DanEC]

I just ran a jumper from one rear light stud to the other and then a jumper from the pass side stud up to the battery. No difference.

Going out to check voltage across trailer relay and voltage at tail lights