'74 2.0 Carbed
Car has been sitting for three months. Starting it occasionally.
I recently put in a new battery. Was starting with no issue.
Then things stopped working.
headlights stopped working, would not flip up.
Wipers
Radio
Today I started and it ran for 30 seconds and just died.
Now the fuel pump doesn't click when I turn the key.

Any ideas of where I can start is much appreciated.

I'm searching through earlier threads just don't know where to begin.

How's the battery voltage? Measure across the posts with a good voltmeter. I'm betting you'll see a lot less than the ~12.6V that shows a full battery.

My guess is that the charging system is not working, so you've drained the battery.

--DD