Some lights blow fuse, others dim, afterwards polarity mixup

The marine industry adopted YELLOW as NEGATIVE. With some battery cases being black, this makes sense.

KRYLON paint for plastic works well. Clean the terminal the battery post and the case around the post. Assemble then spray a splotch of paint over the terminal including the post then around the case.

This lasts a long time and works like a charm.

If your battery is now wired correctly Go to your battery bank right now and use some RED FINGERNAIL POLISH and dab the cables that goes to the POSITIVE terminal. I also always note the STAMPED word 'NEG' or the symbol '-' on the battery case make sure this is the battery cable that goes directly to frame ground which should be close to the battery.

Other people use their cell phone and take a picture of their correct battery cable connections. They leave the photo on the the cell phone so they can pull it up and make sure all is where it is suppose to be.

I have also seen some folks have a see through folder hanging near the battery and have photos or hand drawings in the folder...

Another rule of thumb is if anything is installed inline like fuse holders etc this will most often be the positive line.

Most of us older folks grew up with the Automotive wiring scheme of RED is always Positive and BLACK is always frame ground... The RV COLOR SCHEME follows the house wiring colors where SOLID WHITE is always ground and any wire with color in 'HOT'... some of my installed cable where WHITE but had a color stripe on it indicating they were 'HOT' polarity...

I use the FINGERNAIL POLISH scheme for my cables... A little dab will do ya...

But then again as we get older I probably will forget which polarity the color dabs will be for - POSITIVE or NEGATIVE hehe

The bad thing is it only takes one little spark when you hook up in reverse to do all of this damage. Just one little spark....

I do alot of work around my electrical systems and I still am finding some things wired that doesn't follow the rules... My 12VDC AM/FM JENSON Radio went bad on me and I got a new one. Right out of the box I noticed the fused wire was RED and chassis wire was BLACK coming out of the radio chassis. So at this connection I have a RED WIRE on TOP of a BLACK WIRE. I suppose this causes the really old timers that have left us already to turn over in their grave haha... I have it marked with a POSITIVE SYMBOL and taped...

Roy Ken

Ok most LED lights. you reverse the polarity and they simply do not work, Fix it and they are good again. The LED is kind of an electrical check valve. You put a check valve in a water line backwards. it don't work (Water will not flow) same with the LED's

HOWEVER if they LED's have an electronic controller.... (Dimmer. color selector. effects generator) then ... You may have fried the controller. It is not always protected...Less I install it.

Reversing polarity in a dimming circuit is a nyet nyet. The dimmer takes an even dimmer view of being polarity ambushed. When the circuit throws a tantrum it causes the entire power circuit to do a brownout.

Diodes unless they fry, block voltage in one direction.

Replace the dimmer circuit then see what you have. 555 timer circuit are also reverse polarity short-tempered. Most DC stuff complains bitterly in fact.