Front LED fog lights problem

[aremigij]

Hello,

Previous owner upgraded halogen front fog lights to OEM LED fog lights, but LED lights are flickering. In FORScan cannot find value that I need to change. Maybe someone can help me?

 

[J_C]

Educate me, why would you need or expect a Forscan value to fix this? I mean if they are a binary light source, either always off or full power on, then all they should need is 12V power, no?

I could be wrong but would expect that the prior owner, did this swap and it worked (or else they'd have kept on it to fix the issue, or else put them back to the prior working state?), but now over time they are failing.

Just stating what I would have done, not have left lights in that weren't working correctly and then something would have had to happen after that point for them to flicker now.

Three things I know of that can cause LED lights to start flickering is that over time, heat causes the bond wires to one or more LED dies to come loose, still touching but goes through thermal cycling that causes intermittent connection. The only way to fix that is replace the individual LED(s). 2nd thing in severe temperature change environments is the surface mount LEDs can break solder joints, in which case they can sometimes be reflowed to solve it, temporarily unless it was just a defective solder joint from the factory. 3rd thing is the driver circuit is failing. Driver might be repairable or might be obscured as to the chip markings or potted so not accessible for repair.

What part # are the lights and has anyone done a tear down on them?

 

[peterk9]

Hello,

Previous owner upgraded halogen front fog lights to OEM LED fog lights, but LED lights are flickering. In FORScan cannot find value that I need to change. Maybe someone can help me?

Welcome to the Forum.
How long have you had the vehicle and were the lights working before this started happening?

Peter

 

[aremigij]

The problem is that, as you can see in oscilloscope photo, fog light receive PWM signal. I need switch off PWM or change PWM duty cycle. Fog lights not flickering if it switched on with stopped engine, then engine starts BCM send PWM signal to fog lights and it start flickering.
I have car 1 month and previous owner said about this problem after mounting this led lights it always flicker.
I restore asbuilt data but the problem is not solved

 

[J_C]

^ Where did you take this measurement? If between the driver board and LED array, I'd think your driver is failing.

If this is before the driver, something is very wrong because an incan bulb drive would not be PWM at all, would be continuous 12V, direct battery feed switched on through the fog lamp switch and a relay. Ford has been switching some circuits from the old style mechanical relays to more modern, transistorized relays, and if that happened by '16, that may be where the problem lies and so the next thing I'd do is try swapping that relay with another of same, transistorized relay... except it may not be plug-n-play swappable (see below).

However on the wiring diagram I have for a '14, it shows the older style mechanical relay, but it's embedded in the BCM so not so simple to swap out, and yet it certainly shouldn't be rapidly cycling to product PWM, would be constant on, or off. I am wondering if you are just measuring residual switching noise caused by the LED driver circuit, is there really not any DC voltage near 12V present? I mean your picture just shows ACV.

The correct replacement part for incan fog bulbs conversion to LED will necessarily have a driver (or at least a series resistor if a bad design), and still the input for that should be 12VDC through the BCM, not PWM till after the driver.

This is from the '14 workshop manual:

 

[aremigij]

I measure in fog connector with disconnected fog light

 

[J_C]

Did you measure for DC voltage? The circuit should be feeding the lights, about 12.6VDC engine off, more than that with it on, depending on the state the BMS is in to determine alternator charging cycle. What you measured makes no sense to be correct for the incan bulb so something is wrong in the measurement or the circuit, not in the Forscan setting.

 

[aremigij]

charging voltage is 14+ V, with stopped and started engine fog lights feed is about 12.5V. Because started car fog lights voltage is about 12.5 V but battery charging voltage 14.5V it means that fog lights receive PWM signal and it can seen in oscilloscope photo.
One more question, where in forscan I can disable enable or disable front fog lights outage?
F150 have Front fog lights PWM duty cycle settings, I think ang explorer have this feature:

 

[Arma]

Hi! I'm having the same problem.

I have installed both new modules and LED fog lights:
- Work perfectly with engine off
- Flicker with engine on

2016 Explorer

Anyone has successfully resolved this issue? I'd tip you $50 to know the solution.

 

[peterk9]

Hi! I'm having the same problem.

I have installed both new modules and LED fog lights:
- Work perfectly with engine off
- Flicker with engine on

2016 Explorer

Anyone has successfully resolved this issue? I'd tip you $50 to know the solution.

Welcome to the Forum.
I believe what you are experiencing is hyperflashing. This can occur when you replace incandescent bulbs with LEDs.
Have a look at this video. I hope it helps.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjc0YfR9-CIAxV7FlkFHRDgMUIQwqsBegQIERAF&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DYxaOFSOBkWs&usg=AOvVaw3JvpkZXNl8_jLeaHsN9fht&opi=89978449

Peter

 

[javaleo]

I replaced my front turn signal bulbs with LEDs on our 2018 Explorer. I had to install resistors to stop the hyper flashing of the LED. The BCM saw the blubs as "burned out" until the resistors were installed.

Below is from a 2018 Ford Service Manual.

 

[javaleo]

 

[javaleo]

from a 2018 Ford Factory Service Manual