Front turn signal LEDs cause dashboard problems - Audio & Electronics Forum

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Front turn signal LEDs cause dashboard problems
Tuesday, September 26, 2017 12:15 PM
Hi:

I've been slowly replacing the exterior lighting with LED bulbs. I first changed out the flasher relay with a LED compatible one, next I started with the front and rear marker lights, then the tails.

Up until then everything worked properly and was actually really nice.

When I finally got around to replacing the front running/turn signals with a pair of white/amber switchback LEDs is when I noticed oddities on the dashboard.

When turning on the parking or running lights, both green turn arrows would illuminate on the dashboard. Using with the left or right signal would cause the odometer/trip gauge to faintly flash. Even the driver door chime would make a sickly sound when opening the door with the lights on.

Taking the LEDs out and replacing them with normal incandescent 3157/3357 bulbs made everything go back to normal. I even tried several brands and styles of LEDs, it seems like the front signals simply do not like having LEDs in them.

Does anyone know how to avoid or fix this odd issue?

Thank you in advance!

Re: Front turn signal LEDs cause dashboard problems
Thursday, September 28, 2017 3:13 AM
You need to add resistance to the bulbs. The electronics do no know that they are turning on.




Re: Front turn signal LEDs cause dashboard problems
Saturday, September 30, 2017 5:29 PM
I just wrote a long technical example for this and it got zotted by accident.

I'm not going to rewrite it, it took too long.

Basically, imho, there is no benefit to do that LED replacement if it messes with the car's electronics.

If you insist on doing it, you need to add a resistor ACROSS each lamp to make up the difference in overall current drawn by the original incandescent lamp.

Good luck.

a retired electronics tech.
Re: Front turn signal LEDs cause dashboard problems
Saturday, September 30, 2017 5:37 PM
Steve B. wrote:

I just wrote a long technical example for this and it got zotted by accident.

I'm not going to rewrite it, it took too long.

Basically, imho, there is no benefit to do that LED replacement if it messes with the car's electronics.

If you insist on doing it, you need to add a resistor ACROSS each lamp to make up the difference in overall current drawn by the original incandescent lamp.

Good luck.

a retired electronics tech.



This won't fix his problem at all. The reason why this is happening is because he is running regular 3157 LED bulbs and its shorting out. He needs to run 3157ck bulbs. GM wired 2000+ jbody son differently and since incondecent bulbs don't care about polarity it didn't matter. He needs CK bulbs and he will be fine without a resistor.


<img src="http://www.v6z24.com/jbodyforum/images/signatures/cavalier3400z.jpg" width="319" height="199"/>

Re: Front turn signal LEDs cause dashboard problems
Saturday, September 30, 2017 10:56 PM
Thank you all for the replies.

Since I would rather avoid splicing in resistors, I'll give a pair of cheap CK LEDs a try. I could swear the socket looked standard, with contacts on one side bridged, but I'll cross my fingers and give the CK a go. Fuses are cheap enough if it's incorrect.

Worst comes to worse, I'll just keep the front signals incandescent.
Re: Front turn signal LEDs cause dashboard problems
Thursday, October 05, 2017 3:11 PM
Well unfortunately I was correct and it is in fact a standard socket, not a CK socket. So I guess if I really want to pursue switchback LEDs for my front turn signals error-free is to splice in some resistors.

Thanks everyone for your help and advice.
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Re: Front turn signal LEDs cause dashboard problems
Friday, October 06, 2017 3:23 PM
Mo Jo wrote:

Well unfortunately I was correct and it is in fact a standard socket, not a CK socket. So I guess if I really want to pursue switchback LEDs for my front turn signals error-free is to splice in some resistors.

Thanks everyone for your help and advice.


The rear are ck bulbs not the front. The rear is your issue.


<img src="http://www.v6z24.com/jbodyforum/images/signatures/cavalier3400z.jpg" width="319" height="199"/>

Re: Front turn signal LEDs cause dashboard problems
Friday, October 06, 2017 3:28 PM
Sorry, I should have made that more clear before. The front will take a standard LED bulb, the rear need ck bulbs. If you have ck switch backs put them in the rear and see if it works with th standard in the front. I have LEDs all around my 2000 cavalier.


<img src="http://www.v6z24.com/jbodyforum/images/signatures/cavalier3400z.jpg" width="319" height="199"/>

Re: Front turn signal LEDs cause dashboard problems
Saturday, October 07, 2017 12:07 AM
Rob Dotterer wrote:

Sorry, I should have made that more clear before. The front will take a standard LED bulb, the rear need ck bulbs. If you have ck switch backs put them in the rear and see if it works with th standard in the front. I have LEDs all around my 2000 cavalier.


Everything is peachy keen when the front signals use incandescent and all of the others are LED. The issue only appears when an LED is inserted into the front signals. Since the tails are red either way, a normal red LED is what I'm using, no need for a switchback there. The only reason I want to use switchbacks in the front is because I've long since replaced the OEM headlight housings with some DEPO housings and the turn signals have a clear lens instead of the familiar amber lens.

Looking at replacement tail sockets online, it's definitely CK, however the tail bulbs are happily working without any error. I believe the bulbs they are using are non-polarity.

The switchbacks in the front do work properly, when either the running or parking lights are on they correctly illuminate white and when turning or using hazards they illuminate amber. It's just the dashboard that gets funky.

I've ordered a pre-wired 3157 resistor set that won't require me to modify any factory wiring. When replacing the front signals again, I noticed that an empty socket produces a few similar errors. Fingers crossed that some resistance will correct the issue.



Thanks again.
Re: Front turn signal LEDs cause dashboard problems
Today 2:16 PM
So I just wanted to give an update, the resistors did in fact fix the issue. The only problem was I broke one of the LED bulbs. So it looks like Iím still stuck with incandescent until I can order new bulbs. :p

To confirm again, the resistors did fix the issue though. You need two resistors for both the high and low to eliminate the dash errors.
Re: Front turn signal LEDs cause dashboard problems
Today 3:25 PM
Just a thought did you change out the correct flasher? There are two on gm vehicles. If you changed the wrong one that is why you needed resistors. You should not need them on any jbody. I have a 89, 94, 2000, and 03 with LEDs and no of them needed resistors.


<img src="http://www.v6z24.com/jbodyforum/images/signatures/cavalier3400z.jpg" width="319" height="199"/>


Re: Front turn signal LEDs cause dashboard problems
Today 7:50 PM
Yes, changing out the relay was the first thing I did. I purchased a Novita EP27 LED compatible flasher relay.

Hyper flashing was never an issue. Just dashboard oddities, but in the end it seems like it was a combination off too much power being fed back into the ground due to the reduced current and the bulb-out system not knowing what to do about it.

Adding the resistor harnesses eliminates the issue. I ended up gluing them to some industrial bus magnets and then sticking a couple of heat sinks on them. They fit perfectly into the cavities behind the headlights and attach to the metal securely without frame alterations.

Canít wait to get my new bulbs. Itís my fault one of the previous ones broke, I used a microfiber rag to handle it and it got snagged and tore off a SMD module lol.

Iíll post an update and pictures in a week or two when the replacements come.
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