Electrical Gremlins- 69 Camaro

[g356gear]

I have been working on a car that was restored in 89 and has been sitting since....only 250 miles in 20 years. I am having the following issues....

1. Amp gauge is fine when car is idling. Turn on running lights and the amperage is fine. Turn on headlights and amperage drops. Ideas why? Maybe regulator or faulty alternator?

2. Signals are not working. I am thinking a ground somewhere for this problem since the dash was out to replace the tach that was sticking.