Does anyone know the name of the small single fuse on the Driver side battery. Small black with a flip cover. Has red and black wires to battery cables. What is its function??

I replaced both batteries and accidently it the red wire. Spliced it back and now I'm having idle issues with my 06 Ctd. I have a pic but don't know how to load pics. Any help. I now have 3 codes since this issue. If I knew what it was I could replace it. Thinking it may have to do with the ECM OR PCM. any help would be great.

 

More than likely it is an accessory that was added after the truck was built. To my knowledge Dodge does not have fuses attached to the battery when they leave the factory...

 

I have an 07 I don't have this on my truck at least what I can see. But I was told that you cannot repair these battery cables and they have to be replaced. What kind of problems are you having?