link bad? Dim Eurolights

[Mike Arman]

http://www.isham-research.freeserve.co.uk/quattro   doesn't work . . . have
I inadvertently gotten onto the infamous Kill file? ;-)

Netscrape says "No DNS entry".



When wired correctly, the "aero" eurolights make all kinds of light on both
low and high beams. I even get flashed when I am on low beams, which is
surely a novel experience for any type 44 driver!

What may be happening here is the ground wire is in the wrong position
(socket wired incorrectly), and while the lights are fine on high beam, on
low beam the power is going through the low beam filament (like it is
supposed to) but then through the high beam filament and finally to ground!
That *will* make them dim, even though there is the correct 13 or so volts
at the wire terminal.


These can be a little bit tricky, as the diagrams are reversed between
looking into the face of the socket and looking at the back of the bulb
(which is the same as the back of the socket).


Here's the problem: I have seen CONFLICTING diagrams of the base wiring for
the H-4 bulb! The brightness problem will result from the GROUND being in
the wrong place. Once the ground wire is correctly identified, it is no big
deal to swap the high and low beam wires to get them to light correctly in
regard to the switch.


Bad Ascii art follows:


        _________

       |               |
       |               |


If you are looking at the BACK of the socket, ground is on the LEFT, the
low beam connection should be at the TOP, and the high beam should be on
the RIGHT. 

I you are looking into the FACE of the socket, ground is on the RIGHT, and
high beam should be on the LEFT. Low beam should remain at the top.

Warning - the two diagrams I have disagree! The above MAY be wrong with
regard to the high and low beam connections! The location of the ground
connection is correct and identical on both diagrams.


Here's the conflict: some diagrams have the low and high beam wires
reversed. This will not affect brightness, just which set of filaments will
light. If you have the GROUND wire in the wrong place, however, you WILL
have one set of filaments that work properly and another set that is
distinctly "just along for the ride". The ground wire connections agree on
both diagrams - left from the back, right from the face.

Wired correctly, the  lamp is connected like this internally: 

    >===power to low beam >>/\/\/\/\/\/\ ground /\/\/\/\/\/ <<===== power
to high beam. 


The zigzag on the left will be the low beam filament, and the zigzag on the
right is the high beam filament.


If we mix up the wires like this:

 >===power to low beam>>/\/\/\/\/\ >>power to high beam /\/\/\/\/ ground

high beams will work just fine, but the low beams will be dim because they
are wired in series with the high beam filaments.


NOW: how to troubleshoot it: 1) Definitely establish which terminal on the
bulb is ground (left side, looking at the back of the bulb) and make sure
the wire connected to it does in fact go to a good ground.

2) see that the high and low beams are not reversed, and switch the wires
at the sockets or the relays (whichever is easier) to get the lights in
synch with the switch (high = high, low = low).


This solves two problems at once: a), you wired it wrong in the first place
(no way! Not US!), and b), the diagram you wired it from was incorrect to
start with!


Best Regards,

Mike Arman