After a lot of testing, I found my meter was giving bad results - too
high on voltage. Problem was the 9V battery in the meter was low, so
I replaced it and got good readings to work from.

What I found was a "leaking" fuse. During the process of tracing the
path of power from the battery, I was getting ready to do some fuse
panel checks, and for some onkbown reason, decided to change the 20A
cig lighter/aux power fuse. While out of the circuit, I held it up
to the light and could clearly see the filament between the two
blades was broken. I checked it with a meter set for continuity and
when I applied the test leads, a small LED on the top of the fuse lit
up. The fuse (labelled Smart Glow) is supposed to light up if it
blows so that you can see which one blew. BUt how does it get its
power if the circuit is broken ? I don't know, but apparently it
will allow a reduced amount of voltage to come through the circuit,
which is why I was getting (after meter battery replaced) 10.1 VDC
reading at the lighter/aux sockets.

Now I don't know about you, but I have always understood a fuse,
when working properly, to completely shut down the circuit it was
supposed to be protecting, not allow some power to get through. Maybe
they think the circuit is protected with reduced voltage?

I talked with a technician who verified that these types of fuses
sometines leak like this one - but said in his experience, they did
so all the time, inspite of the manuf's cautions. He said that this
type of fuse causes more problems than it fixes, and besides, if you
know what in the car is failing (wipers, radio,etc.) you just look at
the fuse map found on the fuse box lid and pull and test the
appropriate fuse. He advised me to throw all my spares of that type
in the trash, and go get some "real" fuses, and in addition check to
see if there were any like that in te panel and replace them. I'm
headed out this PM to do this.

Mystery solved, one of those things we used to call a "funny", which
we experienced all the time back in the days of computer mainframes
with discrete component circuit cards.

On 21 Jul 2011 17:51:43 GMT, John Carter wrote:

> After a lot of testing, I found my meter was giving bad results - too
> high on voltage. Problem was the 9V battery in the meter was low, so
> I replaced it and got good readings to work from.
>
> What I found was a "leaking" fuse. During the process of tracing the
> path of power from the battery, I was getting ready to do some fuse
> panel checks, and for some onkbown reason, decided to change the 20A
> cig lighter/aux power fuse. While out of the circuit, I held it up
> to the light and could clearly see the filament between the two
> blades was broken. I checked it with a meter set for continuity and
> when I applied the test leads, a small LED on the top of the fuse lit
> up. The fuse (labelled Smart Glow) is supposed to light up if it
> blows so that you can see which one blew. BUt how does it get its
> power if the circuit is broken ? I don't know, but apparently it
> will allow a reduced amount of voltage to come through the circuit,
> which is why I was getting (after meter battery replaced) 10.1 VDC
> reading at the lighter/aux sockets.
>
> Now I don't know about you, but I have always understood a fuse,
> when working properly, to completely shut down the circuit it was
> supposed to be protecting, not allow some power to get through. Maybe
> they think the circuit is protected with reduced voltage?
>
> I talked with a technician who verified that these types of fuses
> sometines leak like this one - but said in his experience, they did
> so all the time, inspite of the manuf's cautions. He said that this
> type of fuse causes more problems than it fixes, and besides, if you
> know what in the car is failing (wipers, radio,etc.) you just look at
> the fuse map found on the fuse box lid and pull and test the
> appropriate fuse. He advised me to throw all my spares of that type
> in the trash, and go get some "real" fuses, and in addition check to
> see if there were any like that in te panel and replace them. I'm
> headed out this PM to do this.
>
> Mystery solved, one of those things we used to call a "funny", which
> we experienced all the time back in the days of computer mainframes
> with discrete component circuit cards.

Does this relate to an earlier post of yours? It would've been helpful
if you had replied in thread.

It makes sense. Clearly an LED circuit must have a finite resistance, so
as to allow the current to flow that lights the LED. Thus a
high-resistance device would end up powered through the fuse, as long as
there was no low-resistance load also in series with the fuse. For a
hypothetical example, a 100 kilohm LED in series with a 1 megohm load
would reduce the voltage by ~10% instead of cutting it off.

--
Gene E. Bloch (Stumbling Bloch)

John Carter wrote the following:
> After a lot of testing, I found my meter was giving bad results - too
> high on voltage. Problem was the 9V battery in the meter was low, so
> I replaced it and got good readings to work from.
>
> What I found was a "leaking" fuse. During the process of tracing the
> path of power from the battery, I was getting ready to do some fuse
> panel checks, and for some onkbown reason, decided to change the 20A
> cig lighter/aux power fuse. While out of the circuit, I held it up
> to the light and could clearly see the filament between the two
> blades was broken. I checked it with a meter set for continuity and
> when I applied the test leads, a small LED on the top of the fuse lit
> up. The fuse (labelled Smart Glow) is supposed to light up if it
> blows so that you can see which one blew. BUt how does it get its
> power if the circuit is broken ? I don't know, but apparently it
> will allow a reduced amount of voltage to come through the circuit,
> which is why I was getting (after meter battery replaced) 10.1 VDC
> reading at the lighter/aux sockets.
>
> Now I don't know about you, but I have always understood a fuse,
> when working properly, to completely shut down the circuit it was
> supposed to be protecting, not allow some power to get through. Maybe
> they think the circuit is protected with reduced voltage?
>
> I talked with a technician who verified that these types of fuses
> sometines leak like this one - but said in his experience, they did
> so all the time, inspite of the manuf's cautions. He said that this
> type of fuse causes more problems than it fixes, and besides, if you
> know what in the car is failing (wipers, radio,etc.) you just look at
> the fuse map found on the fuse box lid and pull and test the
> appropriate fuse. He advised me to throw all my spares of that type
> in the trash, and go get some "real" fuses, and in addition check to
> see if there were any like that in te panel and replace them. I'm
> headed out this PM to do this.
>
> Mystery solved, one of those things we used to call a "funny", which
> we experienced all the time back in the days of computer mainframes
> with discrete component circuit cards.
>

They've been around since 1976.
I don't understand how they cause more problems than they fix.
It's similar to those Christmas string lights that advertise when one
bulb blows the others stay lit. There is a shunt inside the bulb that
keeps the others lit.
The same in the fuse. There are some fuses in the fuse box that control
more than what is written on the box cover.
When my car's air conditioner didn't work, it turned out to be the
Cigarette lighter fuse that had blown.
The box cover had a separate fuse for the AC, but didn't say anything
about the AC also being controlled by that cigarette lighter circuit.

--

Bill
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeroes after @

"Gene E. Bloch" <not-(E-Mail Removed)> wrote in
news:27u6mwirm5gn$.(E-Mail Removed):

> On 21 Jul 2011 17:51:43 GMT, John Carter wrote:
>
<<<<SNIP>>>>
>
> Does this relate to an earlier post of yours? It would've been
> helpful if you had replied in thread.

I'm sorry. It does, but I'm not on my own computer today, so didn't
have post at hand. The original post, I thought was the same subject,
maybe worded differently.

willshak <(E-Mail Removed)> wrote in
news:(E-Mail Removed) m:

<<<<<SNIP>>>>>
>>>
>>
>> They've been around since 1976.
>> I don't understand how they cause more problems than they fix.

If it had been a "real" fuse that interrupts the circuit, I would ave
measured 0VDC, and since the car battery was OK, I would have looked
immediately at the fuse panel (Occam's Razor) instead of doing power
path checks and trying to figure out just what couuld lower voltage..
Even if the LED glows to show blown fuse, it would not have helped me,
since I don't open electrical boxes with the ignition or accessory
switch on. I would also have a little bit more hair and the neighbors
wouldn't have had to hear how I talk to inanimate objects like cars,
GPS's meters.


>

On 21 Jul 2011 20:05:55 GMT, John Carter wrote:

> "Gene E. Bloch" <not-(E-Mail Removed)> wrote in
> news:27u6mwirm5gn$.(E-Mail Removed):
>
>> On 21 Jul 2011 17:51:43 GMT, John Carter wrote:
>>
> <<<<SNIP>>>>
>>
>> Does this relate to an earlier post of yours? It would've been
>> helpful if you had replied in thread.
>
> I'm sorry. It does, but I'm not on my own computer today, so didn't
> have post at hand. The original post, I thought was the same subject,
> maybe worded differently.

Thanks for the reply.

Since you have now been properly chastised, I can crawl back into my
hole (that's meant to be humor!).

Of course it was good of you to update us (I did somewhat remember the
other thread), and I did mean it as a suggestion, not a criticism.

--
Gene E. Bloch (Stumbling Bloch)

On 21 Jul 2011 20:21:09 GMT, John Carter wrote:

> willshak <(E-Mail Removed)> wrote in
> news:(E-Mail Removed) m:
>
> <<<<<SNIP>>>>>
>>>>
>>>
>>> They've been around since 1976.
>>> I don't understand how they cause more problems than they fix.
>
> If it had been a "real" fuse that interrupts the circuit, I would ave
> measured 0VDC, and since the car battery was OK, I would have looked
> immediately at the fuse panel (Occam's Razor) instead of doing power
> path checks and trying to figure out just what couuld lower voltage..
> Even if the LED glows to show blown fuse, it would not have helped me,
> since I don't open electrical boxes with the ignition or accessory
> switch on. I would also have a little bit more hair and the neighbors
> wouldn't have had to hear how I talk to inanimate objects like cars,
> GPS's meters.
>
>>

That could have been fun to observe and listen to :-)

Computers can have a linguistic effect on me...although my most recent
exercise in colorful language involved plumbing.

--
Gene E. Bloch (Stumbling Bloch)

"Gene E. Bloch" <not-(E-Mail Removed)> wrote in
news:1pvcsf58l5ka7$.(E-Mail Removed):

> On 21 Jul 2011 20:05:55 GMT, John Carter wrote:
>
>> "Gene E. Bloch" <not-(E-Mail Removed)> wrote in
>> news:27u6mwirm5gn$.(E-Mail Removed):
>>
>>> On 21 Jul 2011 17:51:43 GMT, John Carter wrote:
>>>
>> <<<<SNIP>>>>
>>>
>>> Does this relate to an earlier post of yours? It would've been
>>> helpful if you had replied in thread.
>>
>> I'm sorry. It does, but I'm not on my own computer today, so
>> didn't have post at hand. The original post, I thought was the
>> same subject, maybe worded differently.
>
> Thanks for the reply.
>
> Since you have now been properly chastised, I can crawl back into
> my hole (that's meant to be humor!).
>
> Of course it was good of you to update us (I did somewhat remember
> the other thread), and I did mean it as a suggestion, not a
> criticism.
>
Didn't think of it as criticism - I can always use a suggestion and I
appreciate it.