is there any instructions for replacing our negative battery cable ?

There's no separate NEG or POS battery cable, they're part of main harness so it's either splice or replace the whole harness...

Any good splice spots?

godtheater said:

Any good splice spots?

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If you're trying to repair battery terminals and can get new terminals with pigtails, anywhere on the vertical run would be easiest...
Otherwise that'd depend on your objective(s)

it’s noted as a grounding point having problems on 2005 - I want to rule out it being a problem..

Take a set of jumper cables and clamp one end on the battery NEG post and the other end on a good ground point - no need in messing up the harness for 'diagnostic' purposes

Can you explain little more here... what do I do after that? Sorry I am normally good at following ideas / instructions.

First, what is bad, the cable or the connectors?

godtheater said:

Can you explain little more here... what do I do after that? Sorry I am normally good at following ideas / instructions.

Click to expand...

Can you explain what problem you're trying to solve?
If you're just checking ground connections because of flickering lights or some electrical gremlin, you can create a temporary ground circuit with a set of jumper cables to see if it helps...