upper lights not working

[marininn]

My top exterior lights are not working.
The lower ones work fine.
This is a pop top, so there is wiring going up to the top aluminum frame. The lights, there are 4 of them, are run in series -
The 12+ goes to first light then out and continues in and out of the other 3, then the wire out of the last light is grounded (like Christmas Tree lights). So, 12+ into the first one and 12- out of the last one.
I just re-did the 12- ground wire to the top frame for first attempt to fix.
The lights barely come on, at night you can see a faint glow.
These are new LED lights I just installed.
Any ideas where to look for issues?

[marininn]

Only the first light has 12+ and only the last light goes to ground.
I am not quite sure how it supposed to work, as the lights were connected somehow.
So, I maybe need to link the positive wires all together, and not run it through the light, but ground the negative of each light?

[westend]

If they are wired in series (doubtful) you would have 3 volts available at each fixture. More likely, they are 12V wired in a "daisy chain", 12v passed from one fixture to the next and the common ground may be at one point. Measure voltage available at each fixture.
These types of problems are typically associated with a poor ground. The electricity (12V) needs a good path between battery positive and battery ground. Investigate ground potential by measuring with metered resistance between your light's ground location and a clean piece of frame or directly to battery (-) post.