12vdc Bunk Lights Not Working

[Super_Coo]

Hi Guys,

Still trying to resolve this one small issue with our RV.

We bought a used 2006 Innsbruck Supreme i30TBR last year and the lights in the bunk have not worked since we got it.
I was just checking it out this past weekend with a meter and I was getting 13.3vdc at the bulb but neither bulb would work.
I took out those bulbs and tried them in other fixtures and they worked fine. So it's not the bulbs.

They get power from a 12v cigarette type adapter. The previous owner must have forgot to unhook it when bringing in the slide
because it was taped up/repaired with electrical tape and connectors. I did notice that the wire from the new connector compared
to the regular trailer wire was much smaller. I thought maybe it was wired backwards so I tried the other way and the plugin thing
got really hot but still no light. There was 2 large resistors inside the plug... that's what got hot.

I'm going to buy a new more heavy duty plugin thing and try that.
Are the 2 wires coming out of it polarity sensitive in this situation?
I think the bulbs work either way they are slid in. They are 921 bulbs.
The light fixtures look like Camco 41330 on Amazon.

Any advice or suggestions would be greatly appreciated!

Thanks in advance!

[toaobigal]

If you have battery voltage, I would make sure the ground is good at your light.

[Super_Coo]

I checked continuity between the metal plate in the fixture and there was none between it and either side of the bulb socket.
Does that mean I have a bad ground? Or should I have checked between the metal ground of the 12v socket and that metal plate?
I'm not exactly sure how to check. I'm going back this weekend and just wanted be as prepared as possible to try and fix it.

[Super_Coo]

toaobigal - I got a wiring/installation diagram of the Camco 41330 fixture and it just shows a +12vdc(black) and a -12vdc(white) wire coming from it.
I'm going to buy a new heavy duty plugin and wire it in. I'll remove the fixture to make sure I have the + and - going to the appropriate wires from
the 12v wall plate. I'm still unsure of what you meant by the ground... unless it's the -12vdc line.

I'm starting to think maybe the 12v plugin that he wired in because the other had broken might be the culprit.
I opened it up and it had 2 quite large resistors. I'm thinking that the 2 resistors were not allowing enough amps
to pass through to the bulbs... just a guess. And like I said the wires were very small so it was probably some old
cell phone charger or something else that didn't need lots of amps.

[Super_Coo]

Just wanted to mentioned that I picked up a new more heavy duty 12v cigarette type plugin.
I pulled off the light fixture to check the polarity to match it up with the plugin. Wired it up
and now both of my bunk lights work great.