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Old February 26th 05, 02:25 AM
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On Fri, 25 Feb 2005 09:34:04 -0600, "Sharon K.Cooke" >
wrote:

>Not sure about high-powered DC current, but I do know what happens in
>the real world for 12VDC. BTW, I do have an engineering degree, and have
>had several courses in electrical/electronics theory. Also, if it counts
>for "creds", I moonlighted repairing TV sets while I was going to
>school.
>

Heaven help us all - an engineering degree and several courses in
electrical and electronis theory - that explains a lot.
>K`Tetch wrote:
>>
>> On Fri, 25 Feb 2005 08:36:49 -0600, "Sharon K.Cooke" >
>> wrote:
>>
>> >Explain WHAT in a scientific manner? It's a given that if you use a
>> >switch to close a ground, it's easier on the switch and it (the switch)
>> >will last until it breaks simply from mechanical wear & tear. Going the
>> >other way, with a fixed ground and using an electrical path thru the
>> >switch to power the device will burn out the contacts on switches
>> >"before their time". I have replaced a number of MF & headlight switches
>> >(FoMoCo mostly) as proof of that. I have NEVER replaced one on a Toyota.

>>
>> Obviously someone has never been in an electronics/electrical class
>>
>> You know what circuits are, i take it?
>>
>> I work a lot with high-power DC stuff (110V+, at sometimes 1200A) and
>> it doesn't matter where on the circuit a switch is, as, you see, a
>> circuit is a loop, and electron flow goes around ALL of the circuit
>> equally.
>>
>> Why, in your opinion are ground switches better? is it because the
>> electrons 'aren't as tired' as they've only just left the battery, and
>> so can make a cleaner spark at near contact, one which won't
>> deteriorate the contact, unlike if they were positive switched, where
>> they'd be exhausted and jump any old way, destroying contacts?
>>
>> >
>> >Ground switching (of headlights, anyway) has been around for at least 30
>> >years - look at any Toyota or Datsun (Nissan, now) - and has zero to do
>> >with CANBUS, explained as; http://www.cetrek.co.uk/CanbusSet.html
>> >
>> >
>> >
>> wrote:
>> >>
>> >> On Thu, 24 Feb 2005 13:06:40 -0600, "Sharon K.Cooke" >
>> >> wrote:
>> >>
>> >> >Actually, Chrysler likes to do some electrical things the other way,
>> >> >with ground-switched tail lights. Even Ford has done ground-switched
>> >> >tail lights, and the Ford air suspension solenoid valves are all
>> >> >ground-switched. Ground-switching IS the superior way to handle DC
>> >> >switching (less wear & tear on switches), but costs a little more to
>> >> >implement, so the majority of automakers avoid it.
>> >> >
>> >>
>> >> I'd like you to explain THAT in a scientific manner.
>> >>
>> >> The only reason some things are ground switched is to simplify
>> >> electronic control.
>> >>
>> >> Interior lamps are often ground switched, because there are at leat 3
>> >> switches controlling the lamps, and grounding switches on the doors
>> >> are infinitely simpler than power switches in the door jams.
>> >>
>> >> Ground switching rewuires a lot more wiring in most other cases, as
>> >> power must be supplied (by wire) from the battery, and the ground must
>> >> be returned(by wire) to the switch.
>> >>
>> >> With the new can-bus systems, the actual switch can be at the back of
>> >> the car, connected only to the "power" wire which also carries the
>> >> networked control signal. In this case, ground switching may be used -
>> >> and may be the simplest.
>> >> >the fly wrote:
>> >> >>
>> >> >> On Thu, 24 Feb 2005 06:54:50 GMT, "2.3Sleeper"
>> >> >> > wrote:
>> >> >>
>> >> >> >92 Eagle Vision (Intrepid basically). Issues with the tail lights and a
>> >> >> >reverse warning light installation. Someone suggested that it might be a
>> >> >> >negative ground system which will effect the end result of what I was trying
>> >> >> >to achieve.
>> >> >> >
>> >> >> >Anyone have an answer on this one?
>> >> >> >
>> >> >> >Don Manning
>> >> >> >
>> >> >>
>> >> >> Virtually ALL vehicles built in North America since the
>> >> >> mid-1950s have negative-ground electrical systems.


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