1988 Trans Am GTA all LED bulbs front and rear with electronic flash units. Key in on position, turn signals work. Press the headlamp
switch, lamps pop up and lamps turn on- turn signals and flashers don’t work. Dash shows both left and right arrows on and neither the turn signals nor flashers work. Any ideas?

 

Bulbs not in the sockets right (bulb contacts touching both socket contacts instead of only one)

 

All turn bulbs work fine (front and rear) when headlamps not on. I am wondering if the flasher relay for some reason is 1) not good or 2) not heavy enough.

 

No; not least because there's no "relay".

You have a cross on each side of the car between the parking light circuit and the TS circuit, because at least one bulb on each side is not in the socket right. Therefore when the parking lights (note: it's the parking lights, NOT the headlights) are on, the TS filaments get power from the parking light circuit instead of through the flasher, therefore the flasher doesn't flash and the dash indicators light up.

Or, since it seems you've been replacing bulbs, at least one socket on each side is wacked, such that the contacts are touching.

One way or another, you have a cross on each side of the car between the parking light circuit and the TS circuit.

 

Ok so it’s the “park lights” causing the issue but I am still curious how the turn signals function fine with the “park lights” off. The LEDs used were Osram Sylvania wedge base LED bulbs. Not sure you can put them in wrong because the are poke yoked such that one ear is higher than the other.

 

OK now the picture is becoming clearer.

Take out the bulbs and see if the problem goes away. The TSs won't flash but the other things, like the dash indicators coming on, should clear up. If so, you should probably get some other kind of bulbs.

Did they work mostly right (except maybe some not lighting up) when there were regular bulbs in there?

 

This is park function only on.

 

Yes with the incandescents it worked but in my infinite wisdom I wanted the better LEDs (lol).

So my hypothesis is these LED bulbs are not two filament bulbs which is why the problem is occurring. Meaning you can have park or you can have turn but not both.

 

No good deed ever goes unpunished.

 

Update- incandescents back in and they seem to work.

The mystery is the Osram Sylvania bulbs are 2057s and appear to have two filaments. They have the same nubs for poke yoke so one cannot put them in wrong.

 

:shrug:

Oh well, it is what it is, and now you know what that is. Maybe those just won't work in this kind of car. Which would suck.

With different flashers, one specifically for LDEs, the results might be different. Iunno. Kinda expensive to find out. Butt also, kinda expensive to buy all those bulbs. So don't dive too much into the "sunk cost fallacy", butt, if you REALLY want the LEDs, you might want to try that. Maybe one flasher and see how it does.

Also, the side marker bulbs work by being in series with the TS/brake filaments. If those are still incandescents, might wanna try swapping those to LEDs as well, since having the 2 types mixed, probably isn't going to play nice together no matter what flashers you have. You can get red and amber 194 replacement LEDs for those. Those aren't polarized in any way though; be careful to swap them to the polarity that works, if the ones you get happen to need to go in the right way.

 

Well thanks for playing along! Sunk cost is the story of my life but I may dive back into it later. We are getting ready for the Hot Rod Power Tour in 2 weeks so “working” is better than not and the anxiety it was driving. Lol


ok so I was looking at the contacts of the Osram Sylvania LED vs the incandescent bulb. I am wondering if the contacts are touching both the park positive and the turn signal positive causing the issue.