2017 Ford Edge Buzz when Headlights On

Best Answers
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thecardoc3 Member Posts: 5,824
Thanks for the update, sorry for your experience but I know exactly why it is happening.tuffsubject said:6 times in the dealer shop, latest attempt to fix it was replacing the amp and the subwoofer. Problem persists. Next step: replace the audio control module. They do not have the skill or equipment to trace where the signal is coming from. Seems obvious they are just guessing, replacing parts. Surprisingly, this is following Ford's technical support hotline advice.
If an individual technician has made a personal investment in his/her training and knowledge and especially the tools that exceeds "factory" training then that technician would be able to handle this kind of a problem efficiently. But for doing that, the technician would be fed these kinds of nightmares which will pay them less than the time they would have to invest and instead of being rewarded for going above and beyond the average technician they are essentially punished.
That means a tech who avoids learning how to do this kind of stuff gets to do easier work and that means earn a better standard of living.
As far as the tech assist being involved and basically just telling the techs what parts to try and replace, that is par for the course. When the tech assist tells the tech to replace something like the amp and subwoofer, the tech (and the dealer) get paid to replace that component whether it repairs the car or not. If the tech makes that decision and it doesn't fix the car they don't. Tech assist isn't actually measuring anything as I described earlier, and they cannot make a technician who isn't tooled and trained to test that way just suddenly perform testing at that level.
What this all comes down to is the abuse and disrespect that techs have historically had to shoulder has created a significant shortage of qualified people in the trade. The skills of the average technician are way beyond the comprehension of most consumers (and on line experts) but still fall short of the demands of the work that they might have to do. Problems like your Edge's come along once every four or five years for any individual technician and it's impossible to just know what is wrong and extremely difficult to practice the routines and skills that have to be applied to solve them. There is plenty of proof in these very forums for the tendency for outsiders to criticize diagnostic fees because after the solution has been arrived at they suddenly act is if the tech should have just known what the failure was, because maybe an outsiders guess just happened to be correct that time. Where that created a problem is that pressure inevitably served to punish techs for being disciplined and always testing correctly which builds skills and knowledge and in effect had a way to reward them if they shot from the hip accurately, which leads us to where you are at right now.
Want to know a disturbing fact?tuffsubject said:
Also seems obvious that the interference/signal is coming from an external source, is simply being amplified...until they identify the source the problem will remain. We are giving them an ultimatum on next repair visit: return it fixed or provide a replacement vehicle that doesn't have the issue. We'll see how that goes.
It's cheaper for them to buy back a car every once in a while than it is to have a fully trained and capable technician work force. Service and repair in many dealers is still considered a necessary evil and the techs are expenses that have to be controlled. So the dealers pull up short towards making being a technician a truly rewarding career and turn right around and will blame the techs assigned to your car for not knowing what they are doing. Even these forums (and the now defunct answers section) were focused on the idea that someone could simply just know what is wrong with a given car and of course the techs don't know anything (are idiots, morons etc.)
If a young man or woman sitting in a robotics lab in high school or junior college also had the natural skills to be a mechanic decided to become a technician, it would take them about twenty years to be the master technician that you need them to be right now. Twenty years of hard work, constant study, and continuing education while working in a career that would see them paid poorly if at all when they tackle problems like the one in your Edge. I've talked about this for years only to have people try and say that this isn't a consumer's problem. Do you agree with them that this isn't a problem?5 -
thecardoc3 Member Posts: 5,824
Glad they got it solved, now if only techs actually got to earn a living when working through something like this, it would have been solved much sooner. Contrary to most perceptions the engineer's cannot write trouble trees to walk someone through every possible failure. The dealers provide some tools and training but it really requires the technicians to do everything themselves in regards to the kind of training and tooling that are required be ready to solve problems at this level. The rub is the techs have to make this kind of investment while knowing under current management practices they will never be rewarded for having done so and will in all likely hood earn less each year for having invested that much more than the average technician in both their time and personal resources. The technicians who are currently on strike in Chicago is a perfect example of this. The things the techs want would see them compensated for taking on problems like this instead of being forced to do it for free with only a (false) promise that somehow the lost time fixing your car will be made-up to them.5
Answers
ANC. An active noise cancellation issue is plausible. A ground connection "somewhere" as well intended as it might be is misleading and doesn't help. It isn't a "ground loop" which is a general term used by some when dealing with audio amplification when powered by household AC and that isn't going to apply here.
Testing would best be done by first measuring the frequency of the sound. Then comparing that to potential source frequencies. For example the alternator regulator pulses the field control at 400hz. If the noise in the signal matched 400hz or a multiple of that such as 1200hz for a three phase or 1600hz for a four phase then the charging system would become suspect. One has to consider EMI https://en.wikipedia.org/wiki/Electromagnetic_interference from under hood sources. These can usually also be distinguished by frequency and multiples of the engine rpm.
Another way that this can initially be done audibly is with a tone generator. http://www.szynalski.com/tone-generator/
Try playing your recorded sound and varying the pitch from the tone generator at the same time to see when they are "in tune". What you will notice is there will be multiple frequencies that will blend in. A notable one in tune is 208hz. 400hz is definitely not in tune. Which leads me to ask this question. Does the noise change if the engine is running at different speeds?
Using tools like a digital oscilloscope and since this is an audio noise setting it to display AC would be the first choice. The noise might be proven to be in the system source voltage or the amplifier power signal, that would be something within the reach of top technicians. If the sound is digital and being delivered to the amp, that is going to be beyond the scope of any kind of online discussion for now. It's safe to say that if it is digital in nature the techs will be limited to parts substitution and software updates as provided by the manufacturer. The best the techs can do is prove source voltages.
It is intermittent, although it will often stay on for an entire drive round town. Recent visit back at the Ford dealer shop was a bust...issue did not occurafter 36 hours. It resumed this afternoon on a drive and we stopped by the shop again, it quit a few moments after they heard it. It started and stopped a few times while I was there, but it was apparent that unless it consistently buzzes during diagnosis, they won't be able to find the source.
Next step a Ford engineer is going to take the car and drive it a few days to experience the problem. After the July 4th holiday.