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Ann R. Thryft
User Rank
Blogger
Re: Solder blamed for faulty window operation
Ann R. Thryft   3/5/2012 2:44:11 PM

I had the same question as William: why are there so many different PCBs to control the windows? However, I'm not sure about your comment re MCUs, which have been around since the 60s and are usually referred to as "controllers," as they appear to be in this article. True, those older ones were very simple, low-end devices. Perhaps you mean they've gotten fancier than they need to be and the ones used here are unnecessarily complex and/or expensive?


William K.
User Rank
Platinum
Solder blamed, but what was the real fault
William K.   3/7/2012 5:52:19 PM
Ann, yes, it is true that my nomenclature was a bit dated. But still, the question stands as to why add some unreliable and cheaply produced electronics to provide a function that thirty years ago was handled very well by a pair of relays that usually outlasted the car? The current service part sells for a lot more than tose relays did, even after accounting for inflation. And I am certain that current automation could produce a product at least half as good for only a bit more. Besides that, those relays were probably built in the USA, and applicable to many models for a few years, reducing NRE costs a lot.

Amclaussen
User Rank
Platinum
Re: Solder blamed, but what was the real fault
Amclaussen   3/15/2012 3:40:36 PM
Absolutely!  I have the same kind of problem with one of my two Dodges (guess which one), but I suspect this stupid vogue about (ab)using electronics for the most simple and strightforward tasks has gone too far. While my older car (1991) has perfectly operating electric door locks, those design geniuses decided to "save" some wire by multiplexing the door lock switches.  Now the switch has only two wires...

I did a little research (google), and found this (somewhat faulted) explanation, probably written by a overly enthusiastic electronics designer:

"There are 2 resistors in the switch, a 620 ohm for unlock, 2700 ohm for lock and the switch is open at rest.


The switch toggles 12 volts between the 2 resistors.

 

The return wire goes the BCM (Body Control Module) to be interpreted as to what selected position the switch is in.

 

From there the BCM will power the door lock motors in the door latches to lock or unlock the doors. So basically the switch is '2 states plus off' (power in, difference out).


By multiplexing commands on 1 wire (sic), they probably saved 20-30 feet of wire per car on power door locks alone! This saves money, electrical complexity and weight..."


Ooh yeeeaah!!!

This extremely "brilliant" person forgot to say (and understand), that now the damn car NEEDS an overly complex, heavy and very costly to repair "Module", buried deep inside the left side of the dash.  Since the damn module has reliability problems, many owners have discovered the trouble that the "magic" of electronics has created in this design, that means the affected owner now has to resort to a specialized repair center, where the module (no longer serviced by dealers) can be exchanged or repaired for around $400-500 USD not including the hassle of removing and reinstalling it. About 99% of the modules fail after 3 years and the failure is intermittent at first, so that most naive owners (like myself), just continued using the car, and then found the failure became more pronunced and permanent just after car warranty expired.  By the way, Dodge Dealers knew about this, but kept pretending (faking would be more appropriate) that it was a "programming related fault", and that a simple DRB2 manipulation would correct the condition, which was a hoax of course... (The system allows the owner to re-program the door lock action through start key signaling, but the procedure can introduce more serious faults, requiring the tech to perform a much longer keystroking sequence and to request help from factory!)

Since the power locks are interfaced with the theft alarm and remote control, it is not as easy as  simply rewiring the doors and changing the switch connections without losing functionality (at least on my car, the "open" command still works on the drivers side front door).

By contrast, my older Dodge still operates its door locks and windows after 21 years and many miles flawlessly. So much for "progress" and true quality.

As some of you, I love to repair broken things instead of replacing them, but the task of removing the Body Control Module means a heavy, extremely uncomfortable job (it is easy if you have the factory semi-robotic arm at home, which lifts the entire dash assembly and swings it into position inside an almost empty car shell, which is the way they do it at the plant!). Otherwise, you need to hire a dwarf with strong arms and some dexterity. I guess we need to teach the KISS principle to the newer generations of design geniuses, unless we want and can afford to replace the entire car at the first failure!

William K.
User Rank
Platinum
Faulty electrical system faults.
William K.   3/17/2012 2:19:09 PM
The very worst thing that the idiots have done, after switching to the multiplexed system, is to remove the key unlocking function from the passenger side door. How cheap can they get? Presently the only way to unlock the passenger side door from outside also unlocks all of the other doors. In the minivan that is four extra doors unlocked for very unsavory elements to yank open and remove items. Or to jump in and cause grief of various kinds. All this to save the cost of one lock cylinder, probably about $3 in production quantities. I would have been happy to pay $ 10 or even $20 to have that second lock as an extra option, but, instead, some fool decided that there was no need for it. JUst exactly what drove the idiot monkey to think that change was OK?

Amclaussen
User Rank
Platinum
Re: Faulty electrical system faults.
Amclaussen   3/20/2012 11:44:57 AM
"Idiots" was very kind... I would define them  using other words!  What is happening to the so called "design teams" in all the car manufacturers lately?

My wife has bought a new car (Volkswagen Jetta), that lacks the passenger side lock, so that the only way to enter the car is through the driver's side door.   Evidently, the stupid designers have never been trapped in a parking lot in a too cramped space so that you have to enter the car on the other side.

To complicate things a little more, the economy version of this car lacks a remote (even when it has electric door locks), so that you have to open the driver's side door (the only one with a key hole), and then VERY QUICKLY introduce the key into the ignition and turn it to "ON", because the very "clever" designers programmed the damn alarm to sound off BEFORE 20 seconds or so... so that if you don't want to bother your neighbors, you have to be very agile in order to be able to open the lock, open the door, jump inside the vehicle, insert the key and turn it before the all too cautious 20 second period, unless you want to blast everyone with the claxon alarm!  this is NOT a minor inconvenience, because if you are carrying a grocery bag or any other package, you must put it on the floor to be able to deactivate the damn alarm before it goes off... which compromises your own safety... how about that?

Again, what happens to these stupid "designers" ???

nash_weaver
User Rank
Iron
Re: Faulty electrical system faults.
nash_weaver   9/21/2012 5:36:42 AM
honda's really trying their best to improve their designs but this still happens to a lot of people. have been looking here on some models (http://www.drivewire.com/make/honda/) and i think they are improving slowly, too.

tekochip
User Rank
Platinum
Re: Faulty electrical system faults.
tekochip   9/21/2012 8:55:38 AM
What a terrible design!  What if I opened the car just to put something in or take something out?  I don't just open my car door to go driving.

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