Patrick - LED Taillight problems

[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

[DanEC]

I just had a thought (no snide remarks please) - the people who have chimed in on this thread and said LEDs work in their tail lights in ERAs, have the round tail light option which I believe uses 4 bulbs instead of one being a reflector. Kevens2 has round lights, I know Patrick does, I think Large Arbor does. I have the rectangular tail lights with one bulb each.

Possibly, it takes the 4 LED lights together with the front ones to create the resistence properties necessary for everything to work. Without my parking lights on there just isn't enough load in the system and something is going wrong. When I turn on my parking lights the extra load on the system brings everything on and it works fine.

Is there anyone out there who hasn't given up on this thread already, with rectangular lights and had sucess with LEDs in the tail lights.

[patrickt]

I have the rectangular lights. Put everything back together, with the LEDs in the back, and REMOVE the #6 fuse. Try turning on your tail/parking lights. You shouldn't be able to because the fuse is out. Now, try your turn signals and see if they work normally.

[patrickt]

Now, assuming, with Fuse #6 out of the car, and both of the two little fast blow fuses installed properly, the LED turn signal still flashes all four corners regardless of whether you're signalling left or right, then I want you to remove ONE of the fast blow fuses and try the turn signals, in both directions, and report the results.

[DanEC]

Duhh - yeah guess I should see you have rectangular in your avatar. But, I think you have wired in a third brake light too - which may add some load somehow.

I'll see what happens with #6.

[DanEC]

I pulled #6 fuse killing the parking lights. When I turned the turn signals on all 4 corners and license plate light flashed including the parking light led units in the tail lights. Turn the parking light switch on for the heck of it and there isn't any change.

Reinstalled #6 fuse and pulled one fast blow TR fuse. Key on and turn signal on - all 4 corners flash with the one TS direction. In the other direction only the front light flashes and the rear are all dark. License plate light also flashes so turn signal circuit is energized.

Pulled #6 fuse and one TR fast blow fuse, key on, parking lights off, turn signal on - all four corners flash including the parking light led units as well as the flasher ones. Flipped parking light switch on but no different.

Forgot to check with #6 fuse out but I tuned off the parking lights and turned on the turn signals and the panel lights do blink with the lights. I hadn't noticed before as I had the adjustment turned to off.

Grounds still hooked up from lights to battery.

[patrickt]

I think I might know what it is, but I want to be absolutely sure, that with Fuse #6 out of the car, and both fast blow fuses in, with the key on and the turn signal on can you see if the panel lights on your gauges are blinking? I understand that all four corners of the car are blinking.

[patrickt]

You might not have noticed this, but see if when all four corners are flashing, because you're just signalling left or right, and Fuse #6 is out of the car, look and see if the panel lights for your gauges are also blinking ever so slightly. That would be a real clue if that was occurring.

[Xack]

Originally Posted by DanEC

I just had a thought (no snide remarks please) - the people who have chimed in on this thread and said LEDs work in their tail lights in ERAs, have the round tail light option which I believe uses 4 bulbs instead of one being a reflector. Kevens2 has round lights, I know Patrick does, I think Large Arbor does. I have the rectangular tail lights with one bulb each.

Possibly, it takes the 4 LED lights together with the front ones to create the resistence properties necessary for everything to work. Without my parking lights on there just isn't enough load in the system and something is going wrong. When I turn on my parking lights the extra load on the system brings everything on and it works fine.

Is there anyone out there who hasn't given up on this thread already, with rectangular lights and had sucess with LEDs in the tail lights.

Patrick and Dan,
Dan, You did mention that you have 4 blinker relays? or 2? or 1? In most cases the blinker has at least 3 incandescent lights in a normal circuit. Front, Rear and the dash indicator. If you have a blinker relay for each light, the problem may be that each relay only has one LED for it's load. It's not easy to tell from the discussion. Most LED distributors sell loads for the LED blinkers to operate correctly. Do you have something like this installed? However it seems this is the opposite problem... Normally the load is needed to get the relay to blink. All your lights are blinking !! ??? I am cornfused!