Date: Sat, 9 Jun 2012 22:55:47 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Preliminary...Headlight weirdness? (long) Solved!
In-Reply-To: <CAHTkEuK9pAM7K6yJFZr3Q2sxsKsQ6WvVMqrdfatTSwvK5ocBpA@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
All right,
I'm glad that was useful and helpful Don.
'power supply on a load' is not how I would express it at all.
I would say ....think of voltage.
To take it deeper, it's 'potential difference' ...that is ..if we think
or believe that electrons flow from positive to negative ..
if there is a 'difference in potential' ..current will flow.
In most of our DC circuits we think of it as 12 volts on the power side..
and zero volts on the ground side,
thus current flows through the consumer from 12 volts positive to
negative ground.
And we can test on various parts of each circuit .
I did lots of my learning under a car outdoors, at night , in snow and
mud. Drank too much coffee back in those days.
but really ....get any test device, test light, Volt-ohm meter, and
start testing things everywhere.
Particularity, the 12 volt test light is useful for finding power or ground,
or even key-off current drain .
Very useful basic simple tool.
there are far more exotic ones of course..
I tend to like basic stuff and to interact with stuff on a fairly basic
level.
Though it's very fun to try to think of it on a molecular level.
Electrons are magic all right. It appears there is an infinite supply of
them.
And man to they do magic stuff !
what the real Diagnostic Strategy is ..( thinking about your headlights
or whatever )
first you observe a symptom.
Then you think of explanations for that symptom.
then you just test for each explanation you come up with.
over an over until you get that gremlin.
such as 'poor ground could cause that' ..so then you test for that.
or 'blown bulb could account for that' ..then you test for that.
on and on. I call it 'Diagnostic Mind' .
nice to see your post Don.
have fun with the electrons in your van !
Most magical they are.
I am looking forward to turning gravity, or whatever, directly into
electrons.
We are strongly moving forward into the Age of the Electron.
Compared to what is current and emerging technology, our vans are very
crude even.
it's all fun, or should be,
scott
On 6/9/2012 7:26 PM, Don Hanson wrote:
> Hey, I think I just learned here how to test ground? So if I go
> from the power supply on a "load" and go right over to my ground
> connection on that same power user, the test light should light
> up...and if not, the ground is bad..Cool!
> Learning is fun....unless you are doing it under the van in the
> slush with some kind of deadline/destination....
> Thanks, Scott.
>
> On Sat, Jun 9, 2012 at 4:36 PM, Scott Daniel - Turbovans
> <scottdaniel@turbovans.com <mailto:scottdaniel@turbovans.com>> wrote:
>
>
>
> On 6/9/2012 2:10 PM, Don Hanson wrote:
>> When I go to identify the Ground wire in the wiring to the plugs
>> for my headlights...How do I determine that?
>> The ground wires are the brown ones.
> Additionally, a test light can be used to find either ground or power.
>> For example....clip the aligator clip to the front bumper, turn on the headlights ...use the test light to find voltage on a headlight wire. ( should be power on either the high beam wire, or the low beam wire ) Then, stick a paperclip or spade connector into that hot wire, clip your aligatorclip to it...now your ice pick end is 'looking for ground' .
>> Whatever ground it touches will light the light bulb..including the brown ground wires that lead to a decent ground. Always test your test method....like make sure the bulb lights when you touch the front bumper with the ice pick end. The chrome bumpers are always good grounds in my experiece.
>>
>> I would not use a volt meter for this type of test usually. A 12v Test light is real good in a situation like this.
>> I might want to measure how many volts are getting to the end of each headlight wire when they envergized , but for normal tail light/headlight troubleshooting I use a 12 volt test light a lot.
>> If reading voltage on a headlight wire with a meter...you could compare readings between when you are using the front bumper for a ground on your meter's other lead, and the brown ground wire that's at the headlight connector.
>> If say you got 12.1 volts using the bumper for your meter's ground connection ..but only 11.8 volts using the brown wire, you could conclude that the resistance in that ground connection is higher than it should be.
>>
>> Generally you don't need to look at a wriing diagram for testing at the headlight connections. You only need to know one wire is low beams, one is high, and one is ground. Real easy to tell which is which with your test light.
>>
>>
>
>
>
| 
