Can't reach the magic 12v

[BlackJohn]

Originally Posted by Iheartbus

I just meant that I have the 2 batteries in parallel for double the longevity, rather than just using 1 battery.

I see how you think but that doesn't happen in reality with batteries. The weaker one will always bring down the best of the two. It does give you twice the cranking power amperage than one by itself and more reserve capacity to store those amps for accessories etc. More on that later tho,

Pics are helpful to me anyway. ty The pic of the back,can you remove that cover so I can see the printed circuit board that it is. Also, backup from it so I can see wire colour and how many terminals better and how many in total.
You did well but just zoom out a bit, but get the best definition you can.
The front gives many clues so we'll get you on the right track.
Did you get a meter yet? get an old one with a pointer on the dial,much less confusing than digital ones.

[Iheartbus]

My friend's dad is an electrician and he might be able to stop by after work today to help me, but I don't think he has ever worked on these things before. He has a meter.

[BlackJohn]

Originally Posted by Iheartbus

My friend's dad is an electrician and he might be able to stop by after work today to help me, but I don't think he has ever worked on these things before. He has a meter.

Ha, not many of us have worked on them either! Just work at finding the ones with 12v and from what switch does that happen. Make notes, some of those bundles must go to the front of the bus for 12v power and both ways to pick up each light or group being monitored.