<<  <  Page 2/3  >  >>
User Rank
The oldtimers knew better
RAH   10/24/2012 1:39:41 PM
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.

User Rank
Japanese Cars are Better than American Cars... or are they?
Critic   10/24/2012 2:19:31 PM

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?

User Rank
Not Bad Solder but repooled?
wbswenberg   10/24/2012 4:15:07 PM
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.

Larry M
User Rank
Re: The oldtimers knew better
Larry M   10/24/2012 4:35:40 PM
There was a recall on the wiper board on the 1995 GM and Chev trucks for exactly that reason. You could have gotten the board (and installation) free. Unfortunately the same board was installed in my 1995 Chev APV minivan and those were not eligible for the free replacement.

Larry M
User Rank
Re: Japanese Cars are Better than American Cars... or are they?
Larry M   10/24/2012 5:12:01 PM
Critic wrote "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?"

It's got to be true. Even Yugos have better electrical design than General Motors. General Motors' favorite trick is to run more than rated current through their connectors. Example: the A/C-heater blower draws at least 10 amps. The current is switched by a relay with tiny pins which plugs into a Packard connector with tiny receptacles surely not rated for this much current. When it starts to fail, it overheats and melts the plastic base of the relay. This causes the support for the spring-loaded armature to draw away from the Normally-Open contact and the relay ceases to make contact. It's pretty easy to fix the relay--pry off the cap and bend the armature support, possibly while heating the base with a heat gun. After two or three events you notice that the socket contact is mostly burned away.

It fails so commonly that when you go to the parts counter and ask for the heater connector, the parts counterman has it in stock and gets it without looking it up. The GM factory shop manual devotes several pages finding and replacing each of the various connectors used on the car. And the parts counter has the individual contacts for each of the connector sockets, as well as new sockets with pigtail leads.

User Rank
Re: Not good to replace a thermal breaker with a fuse
Fix-it-or-not   10/25/2012 3:33:21 AM
The Honda modules were all exactly the same and were used from at least 1995 to 2003 as these are the years of the three cars involved.  They use through hole components, a single sided PCB and I would be surprised if the total cost of the parts involved amounted to more than $5.00, not that this matters.  They also were not coated with a conformal coating of any sort, although corrosion was not an issue with any of the three.  Again, the problem was exactly the same on all three modules, the relay pin connections had cracked.  None of them had enough solder on them.

The problem is the QUALITY of the manufacture of these devices.  I managed on my vehicle to get 200K Km's before the Day-Time driving lights became intermittant (2003 CRV).  There was no scorching of the solder connections.  The solder was THIN and had cracked.  The other vehicles were a 1995 and a 1998 Accord with less than 100K Km's.

I have been in the electronics industry for over 40 years and have seen some well made products, some well designed products, and many well designed, but poorly manufactured products.  This Honda module was/is poorly manufactured in my opinion.

The GMC manual (yes, we did have one) suggested to replace the headlight high beam, turn signal switch assembly, as did the shops around town, to repair the problem my neighbour had.  When this did not work, he asked me to help investigate the problem.  The problem was the thermal, resetable breaker in the dash mounted, headlight switch.

Someone mentioned that this was a "cost saving" move on GM's part.  You bet it was.  It saved them all of $2 if that.  However, the cost for the replacement turn signal/high beam switch mechanizm is over $600 in Canada from GM and the dash light switch is over $400.  I would rather have paid the extra $2 at the time of manufacture than to get hit with the tab for new switches.  There was a reason that my friend could not find either switch at the scrap yard, even after looking at 50 or so vehicles.  Many people had the same problem.

I appreciate that they used the thermal breaker for the reason that was mentioned by several people.  I take issue that the breaker was hidden within the dash mounted switch and NOT placed at the fuse block where it belongs.  If safety was really their concern, then it would have been acessable so that when it failed at night time, someone would be able to repair the problem and get to their destination.

Interestingly, I have been driving for 40 years, and have never seen my headlights coming on and off as a thermal breaker trips and resets?  Have any of you?  I have driven Mercedes, Honda, GMC, Ford, Chrysler, Volkswagon, Toyota, Datsun, Austin  Healey, Austin Mini's, Beaver Motor Homes, Empress Motor Homes, and a school bus, but haven't seen a thermal, resettable breaker hidden inside a switch in any of them other than this truck.  They all  had accessable over current protection devices.  Yes, even for the headlights.  I am sure there are other models and other manufacturers that incorporate similar methods into their devices but I haven't come across them.

bob from maine
User Rank
Re: Not good to replace a thermal breaker with a fuse
bob from maine   10/25/2012 10:52:20 AM
Regarding lead-free solder. It would appear that after several years the world has come up with an acceptable lead-free solder and developed processes that provide reliable (more or less) solder joints. I have every confidence the EU or someone will discover a new gremlin that will need to be outlawed. Perhaps tantalum or copper, or something like G10 epoxy or RIM plastic. When the politicians apply political solutions to engineering problems the outcome is predictable; the engineering world will complain loudly while quietly coming up with a solution. It's usually easier to deal with difficult physics and chemistry problems than misinformed politicians. Regarding resettable circuit breakers. These have been mounted on the headlight switches seemingly forever. When these breakers cycle, they pit; they are not designed for repeated cycles and if a trailer or running lights are incorrectly wired into a lighting circuit (as would happen on a pick-up for instance), the breaker may cycle with the turn-signals (I've seen this!). Ultimately the breaker will cease to function due to high contact resistance. The purpose of the breaker is to protect downstream wiring without disabling the remainder of the lighting functions (parking lights, dash lights, etc.).

User Rank
Re: Not good to replace a thermal breaker with a fuse
ssco00   10/25/2012 4:01:35 PM
"Someone mentioned that this was a "cost saving" move on GM's part.  You bet it was.  It saved them all of $2 if that.  However, the cost for the replacement turn signal/high beam switch mechanizm is over $600 in Canada from GM and the dash light switch is over $400.  I would rather have paid the extra $2 at the time of manufacture than to get hit with the tab for new switches."


I worked for 10 years preparing electrical system information for GM service manuals.  I clearly remember the time some brillient person removed the rear door courtesy lights, the front footwell courtesy lights, and the glove box light.  The reduction in wires and connectors would save several dollars on each vehicle and they made nearly a half million of that vehicle class yearly.  That is several million dollars per year and I am sure he was honored with a bonus and something to hang on his cube wall. 

This was for the C/K utilities which included the Cadillac Escalade Platinum Edition which went for about $80,000.  And they wokdered why people looking for a vehicle in that cladd didn't even stop at a Cadillac dealer, but went stright to Mercedes, BMW, Lexus, Range Rover, etc.  They even had a TV commercial ridiculing them.  Even my Volvo station wagon selling for half that price has a glove box light and front footwell courtesy lights.  And today, GM seems only a shadow of its old self. 

Also, they are in the business of selling service and replacement parts. 


User Rank
Re: Not good to replace a thermal breaker with a fuse
rkinner   10/25/2012 4:13:34 PM
There was only one vehicle where the breaker did trip and automatically reset, on my 1968 Javelin (AMC).  I was driving from Toledo to St. Louis in the middle of the night and the headlamps suddenly shutoff, and they came back on about a minute later.  Fortunately it was a full moon and we could safely get to the side of I-70 to stop.  It happened twice and then never again. 

Most likely the thermo-breaker got a little hot due to the number of hours we had been driving continuously (no excuse, we should be able to drive 24 hours without this happening).  We never drove that long at a stretch again and the problem never reoccurred.


William K.
User Rank
Automotive headlight problems
William K.   10/28/2012 9:26:19 PM
The reason for using an automatic reset breaker in the headlight circuit is that the headlights are important! If they were fused and a random fuse failure occurred a person could be in a lot of trouble. Momentary short circuits and overloads do happen in cars, and the breaker is supposed to reset and restiore lighting. Unfortunately purchasing gets into the picture and quality is reduced until the price target is met. One of my cars did wind up with a military surplus breaker for the lights. It cost me $2, and while it did trip once or twice it was always able to be easily reset. 

My impression is that many soldered parts in cars are quite poorly soldered, and that the lead free solder is even worse. So perhaps the liability should be placed on those idiots in europe who came up with such a stupid idea. 

<<  <  Page 2/3  >  >>

Partner Zone
Latest Analysis
In this new Design News feature, "How it Works," we’re starting off by examining the inner workings of the electronic cigarette. While e-cigarettes seemed like a gimmick just two or three years ago, they’re catching fire -- so to speak. Sales topped $1 billion last year and are set to hit $10 billion by 2017. Cigarette companies are fighting back by buying up e-cigarette manufacturers.
Microchip recently released the 3D TouchPad, the first USB PC Peripheral device that couples 2D multi-touch input with 3D air gesture technology. The company seeks the help of developers to further enhance the capabilities of the technology.
Made by Monkeys highlights products that somehow slipped by the QC cops.
To give engineers a better idea of the range of resins and polymers available as alternatives to other materials, this Technology Roundup presents several articles on engineering plastics that can do the job.
Mac Cameron of Stratasys describes the company’s Connex3 technology, which allows users to 3D-print complex parts in one build with no assembly required.
Design News Webinar Series
10/7/2014 8:00 a.m. California / 11:00 a.m. New York
9/25/2014 11:00 a.m. California / 2:00 p.m. New York
9/10/2014 11:00 a.m. California / 2:00 p.m. New York
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Oct 20 - 24, How to Design & Build an Embedded Web Server: An Embedded TCP/IP Tutorial
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6

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.
Next Class: 10/28-10/30 11:00 AM
Sponsored by Stratasys
Next Class: 10/28-10/30 2:00 PM
Sponsored by Gates Corporation
Next Class: 11/11-11/13 2:00 PM
Sponsored by Littelfuse
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service