Topo Topper / Matt Gecko LED

I just installed some Matt Gecko led lights in the topper. Everything went smoothly thanks to the easy to follow instructions.
They work great however today I turned them on and it was super dim. Later in the day I tried again and they were nice and bright.

The lights are tied to the starter battery with an inline fuse.

any ideas on where to start?
I’m pretty poor with electronics but not hopeless.
I reattached my ground to a slightly better spot to start but any other ideas would be helpful

 

This I suppose is for my own note taking but if anyone wants to chime in please do.

Resolved the upper issue (connection came loose) but now my new issue is that the lights turn on dim until I drop my tailgate and give it a gentle slam. Then they come on full blast.
Maybe my ground in the taillight is just in a bad spot or potential new connection issue? Still love the lights but dissatisfied in my abilities