I just finished installing an interior roll bar light in my YJ.
I used wire ties to fasten it to my rollbar cover. I used one of the
cheap lights off ebay that use a standard bulb with one wire to the
center and a cheap push on push off type switch.
The tip I have is by running three wires you can have the interior roll
bar light work when the door(S) with switchs are opened or when the
roll bar switch is turned on the roll bar light will illuminate AND the
underdash lights come on. It is real easy. What I did was install the
switch so it interupts the ground wire instead of the hot wire. This
ground wire from the switch goes straight to the frame and is grounded
under a screw. OK now I ran a ground wire from my underdash lights
ground wire to the new roll bar light bypassing the switch on the roll
bar light. while I was under the dash I also used the underdash lights
+ wire to supply power to the new rollbar light eliminating the
additional work of installing a fuse. Now when the doors are opened the
overhead light and underdash lights come on. When someone turns on the
overhead light by using the switch mounted on the roll bar light, the
ground backfeeds to the underdash lights and they come on at the same
time as the new roll bar light. Pretty cool huh.
Offgridman

Until you blow one of the now called 'bulb fuses'....

Man I had a motor bike that died and had to be pushed a few miles home
only to find out the damn burned out tail light was the ignition
fuse.....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Offgridman wrote:

It was my 4H electrical project to find a resistor to run parallel
with the tail light an a '57 Cushman scooter like:
http://www.hobbytech.com/Homepage~pix/MVC-595S.JPG for a very frustrated
club member that kept popping them on our dirt roads, which killed it's
magneto.
God Bless America, ßill O|||||||O
mailto:LWHughes3rd (AT) aol (DOT) com http://www.billhughes.com/

Mike Romain wrote:

Get this, I just remembered my bike is a German Daimler as in the owners
of Jeep! So he is wiring it like they like! LOL!

That is a nice old scooter in the link.

Mike

"L.W.(ßill) Hughes III" wrote:

I am not sure what you mean by bulb fuses. The same fuses that protect
the underdash light will protect the circuit. I used it because it is
labeled correctly and has enough amperage and wire capacity to
illuminate another bulb.
Can you clarify what you mean please?

You told us that your added bonus was the dash light came on,
meaning they were needed to complete the circuit. Like all the lights
must work in a cheap set of Christmas lights.
God Bless America, ßill O|||||||O
mailto:LWHughes3rd (AT) aol (DOT) com http://www.billhughes.com/

Offgridman wrote:

Actually they are not needed to complete the circuit.
The ground for them comes from the door switch when the door is open or
when the dome light switch is activated (remember it is on the negative
wire) then a ground path is provided for them through the dome light
switch. Any one light going out will not stop the others from
illuminating. I never understood why some care manufacturers put a
switch on the ground wires before. Now I see it makes it easy to
control things with one wire from different locations.

When the power goes to a bulb first and the switch is the ground, the
bulb filament becomes a 'fuse'. Daimler wired one of my motorbikes this
way, with the tail light bulb in series with the coil power line.

I am not sure how you wired all of them, but it sounds like you have
several bulbs in series using the ground from the door switch or light
switch to 'power' it up. If they are wired this way, any one bulb
burning out will break the 'ground' line and shut the system down.

If however you have multiple grounds running and everything in parallel
which would be quite the rats nest, then one bulb blowing would just be
one bulb blowing.

Maybe I wasn't reading your description right?

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Offgridman wrote:

I think my description was not very good.
Actually switching the ground to the frame eliminates the rats nest you
envision.
Let me try this again,
one fused hot wire is common to all three of the bulbs center posts and
is wired in parallel instead of series so they do not operate as a
fuse. imagine a ground wire that is connected from one door post switch
to the the other door post switch that interconnects both under dash
lights grounding wires. IF you connect this to ground by opening the
drivers door (this is what the door switch does) then both lights come
on. If you close the drivers door and open the passenger door then
current reverses direction and now flows to the passengers door switch
and to ground. I just added a third door switch so to speak when I
installed the overhead light. I only had to have three wires from the
dome light to the underside of the dash to make it all work. two are
ground wires, and one is a hot wire.
one ground connects to the underdash lights ground wire. This ground
wire is connected to the dome light directly and causes the dome light
to come on when the underdash lights become grounded from one of the
doors being opened. The other ground connects to the frame of the
vehicle under the dash continues up to the dome light switch to on one
side and to the dome lights ground wire on the other side of the
switch. When this switch is activated a ground path exists from the
frame under the dash up through the switch to the dome light bulb.
Since the underdash lights connect directly to the dome lights ground
wire a path for the electricity now continues backwards down this
ground wire to the underdash lights which makes them illuminate.
Now when the dome lights switch is on a ground path will exist
Thanks for taking the time and being polite.
Offgridman

Gotcha.

I also prefer ground switching. When I ran my Hella Black Magic's I
just had to run one small trigger wire to a micro mini switch on the
dash to ground the relay.

I just got confused with your description.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Offgridman wrote: