One of the marker lights had the lens knocked off. Can't find replacement lens so I am replacing the complete light. The new on wires in a little different. Which is the "hot" side and which is the ground side?This is the original

This is a good excuse to go buy a cheap digital meter. Then you can figure it out for certain by using the ohms scale to figure out what wire is feeding the center conductor of the bulb - which will be Pos. Otherwise, since black and white wires are mixed there's really no telling. If the wires going to the new light never touch frame or chassis ground, it doesn't matter what wire goes to each side of the bulb.

Better use the cheap meter to check the actual DC voltage to the lamp to determine the polarity..Good Luck

Take your new light fixture and put the wire ends on a D cell battery. That will tell you which orientation of connection is correct. The lamp will illuminate dimly. Do the same thing for your original fixture to find the orientation.I do agree with the other posters, though, a multimeter will save a lot of trouble in the future.

Major brain fart!! I forgot I have a multi meter. FYI, the brown is the "hot" wire. I kinda thought it might be the brown but was a little confused by the black/white combo

Folks, an incandescent bulb is not polarity conscious. they don't care about polarity and will light just as bright in either direction!

Need a little help?? | Good Sam Community

ScottG
Nomad
Jun 05, 2013
nevadanick wrote:
With one wire it will either have have power and work or 2 grounds and not work. Power goes to the single wire.

The two wires could also be a connection point for the Pos. wire for the next light in the chain. So you cant really go by how many wires there are.
nickthehunter
Nomad II
Jun 05, 2013
What I have determined from this thread, there are a lot of people that fell asleep in their physics classes.
nevadanick
Explorer
Jun 05, 2013
With one wire it will either have have power and work or 2 grounds and not work. Power goes to the single wire.
Dtaylor
Explorer
Jun 05, 2013
Actually the new one is grounded with one of the screws that hold the base to the TT. It has a single wire for the positive side. Since it grounds in this fashion. I would think it would matter.
HJGyswyt
Explorer
Jun 05, 2013
But if you are replacing with a new LED light they are polarity sensitive, so get it right.
Dr_Quick
Explorer II
Jun 05, 2013
12 volt DC bulbs can be connected to either side, as they are not Positive or Negative sensitive. Only Motors are that way, as connecting a DC motor the wrong way will make it run in the opposite direction.

The bulb shown looks like a "194" type, which is made to be installed in the socket shown in any direction. I do not believe that original inquiry was about changing to a LED light.
ScottG
Nomad
Jun 05, 2013
Folks, an incandescent bulb is not polarity conscious. they don't care about polarity and will light just as bright in either direction!
Dtaylor
Explorer
Jun 05, 2013
Major brain fart!! I forgot I have a multi meter. FYI, the brown is the "hot" wire. I kinda thought it might be the brown but was a little confused by the black/white combo
westend
Explorer
Jun 04, 2013
Take your new light fixture and put the wire ends on a D cell battery. That will tell you which orientation of connection is correct. The lamp will illuminate dimly. Do the same thing for your original fixture to find the orientation.

I do agree with the other posters, though, a multimeter will save a lot of trouble in the future.
USAFBILL
Explorer
Jun 04, 2013
Better use the cheap meter to check the actual DC voltage to the lamp to determine the polarity..
Good Luck