[impidan]

Greetings folks,

I recently purchased a US-Spec 300 which had custom-EU-converted stock taillights with separate turn signal (led) and fog (led), working but looking too stock. So I purchased this ones here:

The problems with those is:

• using turn signal will result in emergency flash on the whole vehicle (also front and side turn signals!)
• turn + brake will result in brake only

So, to find any possible faults, I purchased a set of non-modified stock tails and connected them. Turn signal itself working but

- turn + brake will result in brake only. no flashing on taillights anymore.

Is it possible that there have been changes made beside the rear light conversion that I am currently not aware of? The harnesses look stock, also the harness of the converted taillights beside an additional fog-wire.

Driving in public with no turn signal when hitting the brakes is -slightly- dangerous 🙃

Best regards and thanks for any help!

 

[CtCarl]

The installer/upfitter may have made configuration changes with an advanced scantool like AlfaOBD or Appcar's DiagFCA.

You don't mention whether the custom lamps are incandescent or LED. If they're LED, the installer may have added resistors to the front turn signals for load-balancing purposes.

That could explain why neither stock tails nor purpose-built LED units (which presumably would have their own resistors) will work properly.

 

[impidan]

So that would result in the issues I am encountering?

The custom lamps are half-LED (turn, fog) half incandescent (brake, light, reverse) and do have resistors inbuild.

On the front I didn't check yet, that's a good hint indeed. Will check asap.

Did check the front, no LEDs there.

 

[CtCarl]

So that would result in the issues I am encountering?

It might.

The lighting circuits of LX/LC/LD cars are especially sensitive to load sensing issues as they relate to LED upfitting. And unfortunately, BCM configuration changes don't always produce predictable results, so you will sometimes see resistors added in situations and/or places where you might not expect them. In a custom Euro setup like yours, it's difficult to be sure what has been done.

 

[DGO]

From the looks of your profile you're not in the US. If my knowledge of flags is right you're in Germany?

If so you'd be subject to European rules of indicators and rear fog lights. You should have an amber turn signal and fog lights at the bottom of the rear lights by regulation. Some of this at least is programmed (fog lights) I don't know what the difference is for the amber turn signals unfortunately

 

[impidan]

Well, my bad, I may did not clearly set the situation
Yes, I am from germany, BUT the car was imported by an german US-car importer from the US for me and is (or was) an US-Spec car. They (us-car-importer) made the adjustments (whatever that was) to the car before handing it to me.

Beside the tail light mods I discovered when opening them (no changes to the harness) I couldnt find any change made.

DGO is right about the indicator and fog light thing, but nevertheless I want to go back to US-stock.

For the amber lights/turn signals:
Thing is, not that they need (in most, not all) cases to be amber (obviously ) but, differ to US cars (cars that I know) it is not (again, mostly) okay to have the brake light to go off when the turn indicator is flashing. yet there are legal german cars having this feature, but again this is then amber/red and not red/red.

Anyway I would appreciate much your help to get that thing back to original US-specs.

 

[impidan]

So, after browsing with AlfaOBD I got, at least, the remote engine start back to work.
I also played around with some turn- and brake-signal related flags in the software, causing no changes at all.

I also looked through all the tail light harness with the conclusion that there have not been made any changes.

Is there any flag in the OBD-related stuff I am missing? I "just" want to change it back to stock US.

 

[vince56190]

For Alfa ODB paramtrer , to have US taillight , enable COMBINED TAILIGHT In Europe the best Place for this car is Facebook group called "Lancia Thema club de France"