trying to figure out wiring for car project

[Kevin Van Sant]

I've posted this to a couple of honda forums but I thought I'd try a
couple of electronics forums too. I figure even thought this isn't a
"repair" exactly, that it would be a peice of cake for anyone who
knows about electronics. Thanks for any help.

I undertook my project of adding a map light assembly into the
headliner of my 98 civic LS today. I had to remove all the upper
interior trim to pull down the head liner, but it wasn't too bad. I
mounted the map light assembly and have put everything back together.
I haven't figured out the wiring, maybe someone here can help.

My Civic LS 4D is a '98, the dome light has two wires only. One leads
to the battery + , the other comes from the door switches. (I have the
'98 wiring diagram) The grounding comes from being screwed to the
metal frame of the roof.

The map light is from a 2001 Civic EX 2dr. There are 4 wires (see
picture)


http://img168.imageshack.us/img168/4031/maplightyg5.jpg

From looking at it, I'm thinking black is ground, red is (+), but
there is still blue and green. Green is possibly for the door switch
lead, but what about blue which is tied into yellow (thus tied to
white)?

I have to make four wires become three. I'm either going to have to
tie two or leave one out. Anyone have any clearer idea of this than I
do?

As a follow-up, I decided that blue and red were both (+) so tied
them together to the (+) lead. Black was ground, green was door
switches. I wired it up this way and the map lights work, the
original dome works, but the new dome blows the fuse when I turn it
on. The new dome is what's related to the blue wire (if you look at
the picture it should be clear) So evidently I can't just tie it to
the red, although if I exclude it there is no (+) lead to the new dome
light.
Can anyone figure out how I might wire this differently? Thanks.

 

[Tim]

I've posted this to a couple of honda forums but I thought I'd try a
couple of electronics forums too. I figure even thought this isn't a
"repair" exactly, that it would be a peice of cake for anyone who
knows about electronics. Thanks for any help.



As a follow-up, I decided that blue and red were both (+) so tied
them together to the (+) lead. Black was ground, green was door
switches. I wired it up this way and the map lights work, the
original dome works, but the new dome blows the fuse when I turn it
on. The new dome is what's related to the blue wire (if you look at
the picture it should be clear) So evidently I can't just tie it to
the red, although if I exclude it there is no (+) lead to the new dome
light.
Can anyone figure out how I might wire this differently? Thanks.

I think the three wires on the dome light switch will be ground, one
going to the bulbs.
When the witch is off the ground is interrupted, no light, when the
switch is set to door the ground is routed through the door switch and
when the switch is set to on the dome light is routed directly to
ground, light on.

 

[T Shadow]

As a follow-up, I decided that blue and red were both (+) so tied
them together to the (+) lead. Black was ground, green was door
switches. I wired it up this way and the map lights work, the
original dome works, but the new dome blows the fuse when I turn it
on. The new dome is what's related to the blue wire (if you look at
the picture it should be clear) So evidently I can't just tie it to
the red, although if I exclude it there is no (+) lead to the new dome
light.
Can anyone figure out how I might wire this differently? Thanks.

Can't see the wiring well enough to figure it out for sure but may be able
to help anyway.
The four wires would be +(in), negative(frame), negative through door
switches and negative lead (from other dome light). Red should be + and
black the frame. You'll have to figure out the which is which on the other
2.
Spotlights just need + through the bulb and then through the switch to
ground .
Dome lights need + then ground through the door switches or the light
switch.
Basically your applying power to all of the bulbs then the grounding through
the switches determines whether the light is on or off. Looks like what your
calling yellow is the - side of the bulbs, blue is the door switches and
black of coarse ground.

 

[Kevin Van Sant]

Can't see the wiring well enough to figure it out for sure but may be able
to help anyway.
The four wires would be +(in), negative(frame), negative through door
switches and negative lead (from other dome light). Red should be + and
black the frame. You'll have to figure out the which is which on the other
2.
Spotlights just need + through the bulb and then through the switch to
ground .
Dome lights need + then ground through the door switches or the light
switch.
Basically your applying power to all of the bulbs then the grounding through
the switches determines whether the light is on or off. Looks like what your
calling yellow is the - side of the bulbs, blue is the door switches and
black of coarse ground.

Thanks for this (and the other couple of helpful responses from other
posters) The one thing that didn't make sense to me about this is that
if all of the posts on the dome switch are ground then how can one of
them be directly tied into + as well. Anyway, I now have it working
perfectly simply by not using the blue wire. I don't entirely have
it figured out, but I'll leave well enough alone.