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Discussion Starter · #1 ·
I’ve looked on google and seen some threads about the taillights not working but I didn’t see one that mentioned my specific problem. Apologies if I missed it. The problem I’m having is of course the common taillight gone out problem which is causing me to have only one of the three LEDs lit up on the drivers side I was going to just drop the god awful $300 required for one taillight and be done but I noticed something. My front left amber light, the one right above the fog light/robot eye, doesn’t blink on when the turn signal is activated. However this amber light does light up for me if I unlock my car, it just doesn’t respond to the turn signal. I’m not sure if the amber lights on the front of the car are connected because the one that’s built into the side view mirror will blink with the signal. I have no idea about taillights or their wiring so is this normal that that front amber light wouldn’t blink with the turn signal even though the side view mirror one does? I don’t want to spend $300 on something that’s an electrical issue. For reference I’ve accessed the fuse box and trued to reset the fuse but there’s so little info on that for these cars I’m not even sure it was the right one. I’ve also taken the whole assembly out and disconnected all the connectors to no avail. Any help or advice would be greatly appreciated, thank you.

edit: I added some photos that might be of use

Hood Automotive tire Motor vehicle Automotive lighting Bumper
Finger Material property Thumb Nail Electronic component
Car Motor vehicle Vehicle Automotive design Electrical wiring
 

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You did not specify which year Ecoboost you have, but from your wiring harness I'm guessing you have a 2015 or 2016.

The Front Turn Signal bulbs on a 2015-17 are normal bulbs you can get from an auto parts store # 7444NA (vs. '18-21 that now have no replaceable bulbs other than rear side markers, back up lamps, & dome/map lights).

I did have the LH side burn out on my 2016, but I think it was the marker filament and not the T/S filament, so I had nothing unusual going on other than the marker not lighting up on the driver's front side.

Definitely try replacing the front T/S bulb(s) before buying a new taillight assembly !!

Doug
 

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Discussion Starter · #5 ·
You did not specify which year Ecoboost you have, but from your wiring harness I'm guessing you have a 2015 or 2016.

The Front Turn Signal bulbs on a 2015-17 are normal bulbs you can get from an auto parts store # 7444NA (vs. '18-21 that now have no replaceable bulbs other than rear side markers, back up lamps, & dome/map lights).

I did have the LH side burn out on my 2016, but I think it was the marker filament and not the T/S filament, so I had nothing unusual going on other than the marker not lighting up on the driver's front side.

Definitely try replacing the front T/S bulb(s) before buying a new taillight assembly !!

Doug
See that’s the thing, the amber light I’m talking about works. It will light up under certain circumstances but not others. For example if I cut the car off and shut the door and walk away, the light is on but when I press the lock button the light doesn’t light up with the rest. It cuts off even though it was just lit and it doesn’t work during turns which is the real problem. I don’t know if it’s tied to the fact the taillight went out or what.
 

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See that’s the thing, the amber light I’m talking about works. It will light up under certain circumstances but not others. For example if I cut the car off and shut the door and walk away, the light is on but when I press the lock button the light doesn’t light up with the rest. It cuts off even though it was just lit and it doesn’t work during turns which is the real problem. I don’t know if it’s tied to the fact the taillight went out or what.
The 7444NA replaceable bulbs in the front T/S housings have TWO filaments in them.

The brighter one is the T/S and the dimmer one is the parking lamp, and it is possibe for one filament to burn out before the other.

What I'm saying is maybe the parking lamp filament is OK and is what you see light up when you shut the car off & walk away. But when you press the lock button maybe it instead lights up the brighter T/S filament which is burned out and therefore does not light up.

So it is worth pulling the bulb out the back of the T/S housing and trying a new one. Sometimes you can even see that the filament is broken within the bulb.

Doug
 

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Discussion Starter · #7 ·
The 7444NA replaceable bulbs in the front T/S housings have TWO filaments in them.

The brighter one is the T/S and the dimmer one is the parking lamp, and it is possibe for one filament to burn out before the other.

What I'm saying is maybe the parking lamp filament is OK and is what you see light up when you shut the car off & walk away. But when you press the lock button maybe it instead lights up the brighter T/S filament which is burned out and therefore does not light up.

So it is worth pulling the bulb out the back of the T/S housing and trying a new one. Sometimes you can even see that the filament is broken within the bulb.

Doug
So I looked last night and I could see that a separate bulb was illuminating on the right side that’s not illuminating on the left when I pressed the lock button. Now my question is how would that make the taillights not light up? Are they connected somehow in a way that would stop the LEDs in the taillight from lighting up? I’ll go ahead and buy the replacement for the amber bulb but can I expect that to fix the taillight?
 

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On certain older cars it could be an issue, but I'm not sure on new cars with all the electronics ... but it's worth a try !!

Doug
 
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