I kind of think that the contacts - solder joints over heated and you are seeing repooling. I had a problem on my motorcycle with my headlight circuit. While the fuse leads were crimped they corroded. I brighten them up and resoldered with plenyt of resin. Next thing I see is balls of solder. The fuse solder is melting as well as my solder job. Just too much heat I'm guessing from the poor holder contact resistance. Yes, the fusable link was still good.
I admire anyone who repairs his/her own vehicles. Taking a vehicle to an auto repair shop can be an enormous waste of time and money.
I do NOT admire guesswork and trial parts replacement as techniques of automotive diagnosis. These are techniques that are all-too-often used by auto repair shops to extract more money from the customer's wallet. Replacing parts that aren't really bad is good for business, but not good for the customer.
This is a case of "diagnosis by monkeys." The high-beam switch isn't even a good guess as a cause of the headlights not functioning at all. Although the story says that the headlights did not function at night, I suspect that this may be a poor understanding of the symptoms, and that the lights probably didn't work during the day, either. Verification of symptoms is a good first step.
A good second step would be to follow the manufacturer's recommended diagnostic procedure for the verified symptom. This often means that you need to have a factory service manual (not a generic Haynes book) available. Yes, I know these manuals can be expensive or hard to find, but in the long run, they pay for themselves many times over. An Internet search using the symptoms, make, model and year of the vehicle is a good way to find information, but the information may not be 100% reliable.
Following the manufacturer's procedures can also reduce the amount of struggling required to change a part.
As stated in a previous post, it is not unusual for automotive headlight circuits to not have fuses. They often use an automatic-reset circuit breaker. There is a good reason for this, which some auto manufacturers have apparently overlooked in recent years. It is not uncommon for a failing headlamp to cause a current spike that would blow a fuse. On a dark road at night, this could cause a dangerous condition: a car with no lights that cannot be seen by other motorists. It may be interesting to note, also, that headlights typically operate even with the ignition switch turned off. Headlights (and taillights) are important safety equipment!
It is also not unusual for the headlight circuit breaker to be located in the headlight switch. Why? Economics: it minimizes the amount of wire and the number of electrical connectors, and does not require a separate package for the breaker. These headlight circuit breakers are designed (although sometimes by monkeys) to reset automatically.
Is bypassing a headlight circuit breaker with a fuse a clever idea? Absolutely not! It is unsafe. Use an automatic-reset circuit breaker instead of a fuse, if you must avoid replacing the headlight switch. General-purpose automotive circuit breakers are available.
As for the Honda running light modules: process design by monkeys. "...wiring and quality of the Hondas was much better than the GMC?" You provided several examples of electrical problems with Hondas, so I am not convinced this is true. Do you have statistics to back up this statement?
Were the relays through-hole? Was the board single sided with unplated holes? In the 70s as a kid engineer, a senior engineer related some PC board wisdom that they don't teach in school. The one I remember vividly was "Do not use single sided boards with unplated holes in any application that is subject to temperature cycling". The solder will crystalize, crack and give you a cold solder joint. And nothing temp cycles like the inside of a car. This failure mode killed the intermittent wiper board in my '95 GMC pickup and every electronic module in my '83 Mercedes. Mercedes went surface mount to eliminate this bug. Lead free isn't the only mistake here. PCB technology must be suitable for the application.
Good point, Larry. The site went away when the audience lost interest. Component manufacturers switched to lead-free production, the military and aerospace found their sources for leaded parts and the audience quit coming to the lead-free site.
Fix-it-or-not wrote "Now that it is mentioned, it makes sense to use a thermal breaker, but why would it be imbedded in a panel mounted switch??"
Well, they've done that for 60 years or more, too. My '49 Chevy and '55 Ford were both constructed this way. Never a problem in the past. One of the things we haven't mentioned (yet) in regard to lead-free solder is the higher soldering temperatures involved. These shorten the life of electrolytic capacitors and plastic-based components like relays and pots (the latter through thermal stress). So maybe we can blame this on lead-free solder.
And Fix-it-or-not continued "Many people have tried reflowing circuit boards using hot air guns (PS3's and XBOX's) to try and get the solder bumps under the large IC's to re-connect. This is hit and miss at best, and the results are short term if the process does work."
There's been some discussion regarding using your kitchen range oven as a reflow oven. Better control than a heat gun, but still longer duration than the ~5 seconds in a production reflow oven. Likely to shorten the life of other components. I haven't tried this.
And Fix-it-or-not continued "MY take is that the manufacturers love this solder as after 2 years, the customer chucks the device and buys a new one."
Not in the long term. Either you do really expensive product recalls or you get a bad rep for quality and go out of business. Did you know that the product recall of the original Microsoft X-box for the Red Ring of Death failure (a ball-grid array chip that ran too hot and fell off the circuit board) cost over a BILLION dollars?
And Fix-it-or-not continued "The relays used are similar to the Omron G8SE, which isn't a large relay, but has enough mass that vibration will eventually cause a thin coating of solder to crack. Had there been more solder used, this most likely would not have happened."
Ahh. not easy to do, especially with lead-free solders. If you are doing everything with one pass, you need to pick process parameters (time, temperature) to just adequately heat the big, heat-sinking components without overheating the delicate surface-mount stuff and the capacitors. A combination of surface-mount and pin-through-hole components makes this even harder. IT was easier with the lower-melting-point and better wetting characteristics of Pb/Sn solder.
I really do think DesignNews could do us a service here by serving as a focal point on this problem.
Larry, Design News ran a mini site on the subject of RoHS and REACH for years. We engaged industry groups and who were challenging the EU on the technical aspects of RoHS and REACH. We also involved manufacturers and distributors in the site. Going further, we ran strories using whistle blowers as sources. We brought in the voices of all of the major experts we could find -- on both sides of the issue.
At a certain point, the industry moved on, though industry groups are still involved in the ongoing developments in RoHS and REACH.
Now that it is mentioned, it makes sense to use a thermal breaker, but why would it be imbedded in a panel mounted switch?? There are other breakers in the fuse blocks, so one more wouldn't hurt. A replacement cost from the dealership of around $400 for the switch module, because of a $1 part that is intended to fail, seems to me to be a cash grab, especially when the breaker could have been located where it was accessable. Please note that when this breaker failed, the lights were completely unsafe! If the lights were turned on so that the clearance lights worked, there were no headlights. If the light switch was off so that there were no clearance lights, then the Day-Time running lights functioned. So, if the breaker failed on the road at night, who ever was driving this particular vehicle would have been stranded. Day-Time running lights might let you see where you are going late at night (barely), but the chances of being rear-ended by someone else because your clearance lights are not on is greatly increased!
I agree with everyone about the current trend in the lead free solder. It is very problematic. As a side job, I do repairs on consumer equipment, more to keep me busy than anything else. The number of pieces of equipment that fail because of this solder is unbelievable, and much of it is non-repairable. Many people have tried reflowing circuit boards using hot air guns (PS3's and XBOX's) to try and get the solder bumps under the large IC's to re-connect. This is hit and miss at best, and the results are short term if the process does work. MY take is that the manufacturers love this solder as after 2 years, the customer chucks the device and buys a new one. However, the idea of using lead free solder was to be ecologically friendly. Using this solder has had the opposite effect.
The Day-Time running light modules in the Honda's did not have enough solder on the boards. At best, there was a thin film used, suggesting that a few cents were saved by not using an appropriate amount of solder. The relays used are similar to the Omron G8SE, which isn't a large relay, but has enough mass that vibration will eventually cause a thin coating of solder to crack. Had there been more solder used, this most likely would not have happened.
My CRV has over 200K KM's on it, so I can't complain too much about the failure of the Day-Time running light module, it just seemed interesting that three different vehicles all had the same problem with the same module. How many more are there out there with the same problem?
This has been a really interesting discussion - I didn't know that about self-resetting thermal breakers...a seemimg failure is actually a safety feature designed in on purpose...
I was also interested to learn about the solder issues. My first thought was not poor quality solder but poor soldering practices. Just goes to show that one should dig a bit deeper to get the complete picture sometimes. Fortunately the fix is the same as long as the author used "the good stuff" in his repairs.
The first Tacoma Narrows Bridge was a Washington State suspension bridge that opened in 1940 and spanned the Tacoma Narrows strait of Puget Sound between Tacoma and the Kitsap Peninsula. It opened to traffic on July 1, 1940, and dramatically collapsed into Puget Sound on November 7, just four months after it opened.
Noting that we now live in an era of “confusion and ill-conceived stuff,” Ammunition design studio founder Robert Brunner, speaking at Gigaom Roadmap, said that by adding connectivity to everything and its mother, we aren't necessarily doing ourselves any favors, with many ‘things’ just fine in their unconnected state.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.