verybored

So my passenger tail light has dimmed. You can barely see that the LED light are still lit. I went to Advanced Auto Parts for some advice and was told that it could be a power source(he used another word and I can't recall what was it now) in the tail light. He said that if I wasn't handy with a soldering iron I should just buy a new one. Then he told me a new one would cost about $400. I would like think that getting handy with a soldering iron would be cheaper. Problem is that I don't know what the part I need to order is called, where in the tail light it's located. You know the important stuff one would need to know in order to repair something. Can anyone please help with this information.


I believe these are my tail lights. I can take a pic of today if it's different.

Thanks for any and all help I can get with this.