Cars have used self-resetting thermal breakers instead of fuses on the headlights as early as the 1940s. There's a reason for this. On a pitch black country road on a cloudy moonless night, you don't want to be pitched into sudden darkness--and with no way to get home, just because wire insulation chafed through someplace.
You might be able to find and replace that fuse in blackness, but could your wife?
Better that you or she should drive home with blinking lights, cycling at a rate low enough to prevent fire or further wire damage but high enough for safety--to see and be seen.
You wrote ". The problem was immediately apparent: several cold solder joints on one of the relays. I re-soldered every joint on the board because there was so little solder used in manufacturing that future failures were inevitable. Sure enough, the problem was solved.
"We then pulled the module on his Accord and found exactly the same problem -- exactly the same pins, even! The same remedy with the same result, the problem was resolved."
Not at all surprising. The misguided European rulings changing the composition of solder has resulted in formulations that are brittle and become more brittle with age. Electrical appliances, cellphones, cameras, music players, and cars are all failing prematurely due to this terribly ill-considered decision. I received a set-top box sent from 200 miles away, and received it with a surface mount IC (BGA) rattling around in the bottom.
I am sure you made the repairs with 60/40 or 63/37 Pb/Sn solder which should have been used in the first place.
This is not to mention the "tin-whisker" problem, also caused by the new solder formulations and suspected of causing the runaway Toyota accelerations.
I agree, I've seen it over and over. Themes solder formulations make such ugly looking joints that it's nearly impossible to tell from a visual examination if the joint is good or not. The EU really has to examine this issue again. I think they made a bad call.
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.
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?
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.
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.
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.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.