E34: License Light works but error message displayed

I get an error message that my license plate light is out. Both were
working but were very dim. I replaced both that they are just as dim as
before. I noticed that when I removed one (while lit) the other lamp got
much brighter. Error message remains w/ new bulbs.

This car was damaged several years ago and body work was done to the trunk
lid. I may have just answered own question.........

Chip L

In article >,
Chip L > wrote:
> I get an error message that my license plate light is out. Both were
> working but were very dim. I replaced both that they are just as dim as
> before. I noticed that when I removed one (while lit) the other lamp
> got much brighter. Error message remains w/ new bulbs.

> This car was damaged several years ago and body work was done to the
> trunk lid. I may have just answered own question.........

Sounds like you have a high resistance connection somewhere. My bet would
be the ground. Try adding a ground temporarily with a bit of wire to the
main bodywork.

--
*Just remember...if the world didn't suck, we'd all fall off.

Dave Plowman London SW
To e-mail, change noise into sound.

"Chip L" > wrote in message
...
>
> I get an error message that my license plate light is out. Both were
> working but were very dim. I replaced both that they are just as dim as
> before. I noticed that when I removed one (while lit) the other lamp got
> much brighter. Error message remains w/ new bulbs.
>
> This car was damaged several years ago and body work was done to the trunk
> lid. I may have just answered own question.........
>
I reckon you have the wrong wattage lamps fitted. The giveaway is that the
remaining lamp gets brighter when one is removed. (the higher than normal
total wattage means that excessive current is being drawn and resulting in
significant volt drop hence the dimmer than usual lamp output. The light
control module senses lamp current and has upper & lower limits
'programmed-in', so if one or both fail, the current will be out of spec and
a warning will be given.
The guys who fit LED repeaters (much lower wattage than incandescent lamps)
find this out in short order too.

JB

"JB" > wrote in message
...
>
> "Chip L" > wrote in message
> ...
>>
>> I get an error message that my license plate light is out. Both were
>> working but were very dim. I replaced both that they are just as dim as
>> before. I noticed that when I removed one (while lit) the other lamp got
>> much brighter. Error message remains w/ new bulbs.
>>
>> This car was damaged several years ago and body work was done to the
>> trunk
>> lid. I may have just answered own question.........
>>
> I reckon you have the wrong wattage lamps fitted. The giveaway is that the
> remaining lamp gets brighter when one is removed. (the higher than normal
> total wattage means that excessive current is being drawn and resulting in
> significant volt drop hence the dimmer than usual lamp output. The light
> control module senses lamp current and has upper & lower limits
> 'programmed-in', so if one or both fail, the current will be out of spec
> and
> a warning will be given.
> The guys who fit LED repeaters (much lower wattage than incandescent
> lamps)
> find this out in short order too.
>

Nope. If you pull off one lamp the other one would stay the same brightness
no matter what wattage lamp you put in there.

The only way he gets that symptom is if there is something resistive in the
circuit (like Dave said) either in the supply side wiring or ground. It is
supposed to be a straight shot with the only resistance to the 12v supply
being the wire and contact resistance.

You could measure the voltage at the contacts at the bulb socket with the
bulb in place and find out where the problem is. The hot side should be 12v
and the ground side should be almost zero. If the hot side is something
less than 12v you have a resistance in the supply wiring. If the ground
side is anything more than a few millivolts you have a ground problem.

Hope that helps,
MaltHound

"The Malt Hound" <Malt_Hound@*no spam please*yahoo.com> wrote in message
...
>
> "JB" > wrote in message
> ...
> >
> > "Chip L" > wrote in message
> > ...
> >>
> >> I get an error message that my license plate light is out. Both were
> >> working but were very dim. I replaced both that they are just as dim as
> >> before. I noticed that when I removed one (while lit) the other lamp
got
> >> much brighter. Error message remains w/ new bulbs.
> >>
> >> This car was damaged several years ago and body work was done to the
> >> trunk
> >> lid. I may have just answered own question.........
> >>
> > I reckon you have the wrong wattage lamps fitted. The giveaway is that
the
> > remaining lamp gets brighter when one is removed. (the higher than
normal
> > total wattage means that excessive current is being drawn and resulting
in
> > significant volt drop hence the dimmer than usual lamp output. The light
> > control module senses lamp current and has upper & lower limits
> > 'programmed-in', so if one or both fail, the current will be out of spec
> > and
> > a warning will be given.
> > The guys who fit LED repeaters (much lower wattage than incandescent
> > lamps)
> > find this out in short order too.
> >
>
> Nope. If you pull off one lamp the other one would stay the same
brightness
> no matter what wattage lamp you put in there.
>
> The only way he gets that symptom is if there is something resistive in
the
> circuit (like Dave said) either in the supply side wiring or ground. It
is
> supposed to be a straight shot with the only resistance to the 12v supply
> being the wire and contact resistance.
>

My vote is on a ground.

"Jeff Strickland" > wrote in message
...
>
> "The Malt Hound" <Malt_Hound@*no spam please*yahoo.com> wrote in message
> ...
>>
>> "JB" > wrote in message
>> ...
>> >
>> > "Chip L" > wrote in message
>> > ...
>> >>
>> >> I get an error message that my license plate light is out. Both were
>> >> working but were very dim. I replaced both that they are just as dim
>> >> as
>> >> before. I noticed that when I removed one (while lit) the other lamp
> got
>> >> much brighter. Error message remains w/ new bulbs.
>> >>
>> >> This car was damaged several years ago and body work was done to the
>> >> trunk
>> >> lid. I may have just answered own question.........
>> >>
>> > I reckon you have the wrong wattage lamps fitted. The giveaway is that
> the
>> > remaining lamp gets brighter when one is removed. (the higher than
> normal
>> > total wattage means that excessive current is being drawn and resulting
> in
>> > significant volt drop hence the dimmer than usual lamp output. The
>> > light
>> > control module senses lamp current and has upper & lower limits
>> > 'programmed-in', so if one or both fail, the current will be out of
>> > spec
>> > and
>> > a warning will be given.
>> > The guys who fit LED repeaters (much lower wattage than incandescent
>> > lamps)
>> > find this out in short order too.
>> >
>>
>> Nope. If you pull off one lamp the other one would stay the same
> brightness
>> no matter what wattage lamp you put in there.
>>
>> The only way he gets that symptom is if there is something resistive in
> the
>> circuit (like Dave said) either in the supply side wiring or ground. It
> is
>> supposed to be a straight shot with the only resistance to the 12v supply
>> being the wire and contact resistance.
>>
>
> My vote is on a ground.
>

Agreed. I'd bet the ground wire or strap between the trunk panel and the
rest of the car has gone tango uniform. But there is also the possibility
of a problem in the headlight switch. A meter check would tell for sure...

MaltHound

Thanks a bunch, guys.


"The Malt Hound" <Malt_Hound@*no spam please*yahoo.com> wrote in message
...
>
> "Jeff Strickland" > wrote in message
> ...
> >
> > "The Malt Hound" <Malt_Hound@*no spam please*yahoo.com> wrote in message
> > ...
> >>
> >> "JB" > wrote in message
> >> ...
> >> >
> >> > "Chip L" > wrote in message
> >> > ...
> >> >>
> >> >> I get an error message that my license plate light is out. Both
were
> >> >> working but were very dim. I replaced both that they are just as dim
> >> >> as
> >> >> before. I noticed that when I removed one (while lit) the other
lamp
> > got
> >> >> much brighter. Error message remains w/ new bulbs.
> >> >>
> >> >> This car was damaged several years ago and body work was done to the
> >> >> trunk
> >> >> lid. I may have just answered own question.........
> >> >>
> >> > I reckon you have the wrong wattage lamps fitted. The giveaway is
that
> > the
> >> > remaining lamp gets brighter when one is removed. (the higher than
> > normal
> >> > total wattage means that excessive current is being drawn and
resulting
> > in
> >> > significant volt drop hence the dimmer than usual lamp output. The
> >> > light
> >> > control module senses lamp current and has upper & lower limits
> >> > 'programmed-in', so if one or both fail, the current will be out of
> >> > spec
> >> > and
> >> > a warning will be given.
> >> > The guys who fit LED repeaters (much lower wattage than incandescent
> >> > lamps)
> >> > find this out in short order too.
> >> >
> >>
> >> Nope. If you pull off one lamp the other one would stay the same
> > brightness
> >> no matter what wattage lamp you put in there.
> >>
> >> The only way he gets that symptom is if there is something resistive in
> > the
> >> circuit (like Dave said) either in the supply side wiring or ground.
It
> > is
> >> supposed to be a straight shot with the only resistance to the 12v
supply
> >> being the wire and contact resistance.
> >>
> >
> > My vote is on a ground.
> >
>
> Agreed. I'd bet the ground wire or strap between the trunk panel and the
> rest of the car has gone tango uniform. But there is also the possibility
> of a problem in the headlight switch. A meter check would tell for
sure...
>
> MaltHound
>
>