electrical problems 1993 ln130 2.4L surf

Hi all

not a mechanic but can sort out how to do some work

bought my surf a year ago

low Kms but has had issues that until now I’ve lived with but I need help diagnosing and potentially locating the physical locations of stuff to troubleshoot 

issues:

1. Headlights not bright so switched to LED but now have no highbeam 

2. at various grounding pointsthroughout the engine I measure +5.7V which I presume affects the headlights 

3. When idling I can hear the parking relay click in and out 

4. various dash lights will come on randomly (like 4x4 ) when the items are not engaged

5. recently my auto lock and windows stopped working 

6. in the last year my brake lights have burnt out twice

I presume it is all tied to a short somewhere.

i checked the voltage regulator and it showed 13.96V when idling and when revved so I assume that isn’t the issue?

I have the service manual from Australia but it doesn’t say much at all and doesn’t show locations of various relays 

im looking for any help you can give. I’m in BC and parts to here are expensive and I’d like to fix this as it’s a great off road rig I’d love to keep

ask any further questions or give me suggestions and I’ll try to sort this out

i may be a little unresponsive at times as I have a new baby and house renovations ongoing but I do need to sort this out

thanks in advance