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Sherlock Ohms

Strange Connections Killed the Mercedes-Benz

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rollywind
User Rank
Silver
cost vs. value
rollywind   11/23/2015 11:27:52 AM
NO RATINGS
It has been my experience that BMW produces great mechanicals but lousy electronics and electrical products. You must know that they produced cars in the 80's and 90's specifically for the leasing market. Robust design (proper design) was not their priority.

I helped a friend remove his dash to replace several burned out light bulbs and found the PC board behind the dash to be made of similar materials to the board used in the sonobouy* dispatched at sea by the navy during ASW operations. These boards were very simple design and meant to last only about 12 to 24 hours and then sink. The board had cracked, not unusual with this material, and the solder connections were poor with several of the failures attributed to the brass light sockets detaching from the solder on board.

My daughter's BMW left tail lights totally stopped working one day. Turns out the base metal for the three light bulbs was made of cheap pot metal (white metal) and the connection to ground for all three ran through an 18 gauge wire to the car's chassis. The push on connection had charred and the wire opened due the high current and poor connection. I rebuilt this by soldering a new wire with push on connector to a spare tab on the base using a 12 gauge wire. I eventually rebuilt all of the signal light connections on the car.

We're also aware of those who think they know business when all they really know is the jargon of business--often number crunchers who, as Oscar Wilde put it, "know the price of everything but the value of nothing."   From the forward to the book: Seeing the Big Picture by Kevin Cope

I survived the '89 Quake also.

*A sonobuoy (a portmanteau of sonar and buoy) is a relatively small buoy (typically 13 cm (5 in), in diameter and 91 cm (3 ft) long) expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic research.

patb2009
User Rank
Platinum
Re: over-engineering
patb2009   11/4/2015 5:37:04 PM
NO RATINGS
very few cultures survive a race to the bottom.

 

If your competitors can do something cheaper and sell cheaper, 

odds are you will lose the market.

 

 

patb2009
User Rank
Platinum
Re: over-engineering
patb2009   11/4/2015 5:36:00 PM
The manuals should be supplied on either a USB or a DVD as a standard.

Larry M
User Rank
Platinum
Re: over-engineering
Larry M   11/4/2015 12:46:35 PM
And include lifetime map updates for the GPS.  $200/year for updates doesn't compare well to $39.00 for a standalone GPS with lifetime maps.

sdgengineer
User Rank
Silver
Re: Two similar instances
sdgengineer   11/4/2015 12:36:07 PM
NO RATINGS
My 2000 GMC  truck did the same thing.  I got a new ODBII/CAN reader, plugged it into the port to see how it worked and ...nothing.A quick google search revealed that the lighter fuse powered the ODB reader as well.  Probably standard across GM cars..

William K.
User Rank
Platinum
Re: over-engineering
William K.   11/4/2015 12:15:11 PM
NO RATINGS
"If the leaders could instill a culture of excellence". RIGHT, the leaders primary goal is to increase share prices to make the board and the shareholders happy. Possibly such inspiration could come from lower level managers and supervisors, and sometimes it does. But the auto companies have other goals and pulls.

vandamme
User Rank
Gold
Re: under-documenting
vandamme   11/3/2015 11:20:34 AM
NO RATINGS
If somebody builds an open source car, I'll buy it.

John_Reed
User Rank
Gold
Re: over-engineering
John_Reed   11/3/2015 11:14:47 AM
Spending over $20K for a product and not being able to get documentation that the owner could use to troubleshoot, or at least supply to an independent technician for repair is an outrage.

The last official car manuals I bought was for a '93 Taurus. I think the service manual cost $100 and the wiring diagrams another $15 or $20.

If the "consumer advocates" in Congress want to accomplish something they ought to require that auto manufacturers supply all service manuals on a DVD or other medium at a reasonable cost as an option for the buyer.

 

J.Lombard
User Rank
Silver
Re: over-engineering
J.Lombard   11/3/2015 11:06:08 AM
NO RATINGS
This type of list would have been very helpful to me last year when the emergency flashers in my 2005 BMW X5 became enabled, with no way to disable them. I swithed the flashers on while parking a trailer in my driveway. When I tried to shut them off, the console mounted push-button had no effect.

BMW does not use a mechanical swith to energize the flashers. Instead, the button pushes a plunger that contacts a micro-switch on a small circuit board mounted underneath. The retaining tabs on the circuit board had broken loose from the switch housing, rendering the plunger useless and the flashers merrily blinking away.

It was about 10PM and I was just wanting to call it a day. I figuerd the easiest way to kill the flashers woud be to pull the fuse for the circuit, else the battery would be discharged during the night. I suppose I could have disconnected the battery, but it is located in the rear of the vehicle, under the load deck, under the spare tire, AND under the air compressor for the load leveling shocks.

I started pulling every fuse that even looked like it had a "lighting" function label on the fuse box cover(s). After pulling about a dozen fuses, the lights were still issuing their warning message.

In a fit of desperation, I pried the switch housing out of the console and discovered the mechanical failure. I was able to poke the micro-switch with a small screwdriver and deenergize the flashers, allowing a permanant fix later.

I can just imagine what a poor outcome this could have caused if this had happened at the airport paking garage or similar not-home location. If a listing would have been provided in the manual, the fuse could have been located and the emergency (flashers) alleviated.

John_Reed
User Rank
Gold
shorts and opens
John_Reed   11/3/2015 10:46:48 AM
NO RATINGS
Given accurate diagrams, or even better, computerized wire listings, opens are easy to find as long as you can get physical access to conductors. Shorts are another matter, and intermittant shorts can consume inordinate amounts of time and expense.

At my plant we had two contractors simultaneously installing two major upgrades in the same bay of a building. Both teams had hand drawn wire lists and both started numbering their wires sequentially with wire #1. Many of the wiring junctions were in boxes that were very hard to access. There were no terminal strips in many of the junction boxes and we ended up with many cases where the two systems had totally unrelated conductors tied together labeled with identical wire numbers.

 It was a perfect storm of confusion. When checkout began, some components immediately went up in smoke. Wire #1 of system A was connected to wire #1 of system B. When this was corrected we got all the way to wire #3 before dealing with the next error.  It took months to correct all the errors. All this waste of time and effort would have been avoided had management simply specified to the contractors a numbering system to use in identifying cables and conductors.

There is no excuse for failing to document every conductor in a newly constructed facility in a data base, which can be sorted to show all the terminal points connected to any electrical circuit node or all the electrical nodes on each terminal strip or subassembly connector.

 

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