Battery wiring question

[Janine]

Does anyone know if the wiring in this photo is correct for wiring Rv batteries in parallel? A couple years ago a friend replaced a battery and it has not worked properly since. For example, the aux on/off switch stopped working. I rewired via internet photos last Fall and thought I had it working but now the aux switch is not working again and batteries are not charging. It could be the batteries but the aux switch not working again has me thinking it is something else. I had the batteries tested last fall and they were fine and the Rv was plugged in all winter. However, if the wiring was incorrect then they probably were not charging. I’m especially wondering about the two small wires. Thanks so much for any advice!

 

[BGMAC]

I can’t really tell the pos and neg terminals in the pic. Is the switch on the neg or pos terminal?