No signal lights 72 Custom 20

[67GMCcampercruiser]

I recently acquired a 1972 Custom 20. I installed a rebuilt starter and turned the 350 engine over. Then click click nothing. Replaced the alternator with rebuilt as the brushes in the old one were done. Starter shop says there is something robbing power from the starter. I have all the lights working but no signal lights. Pulled the steering wheel and installed a new signal switch. Nothing. I'm thinking maybe the signal problem and lack of power to the starter are related. To the right of the fuse box is some type of relay or something that has 3 wires black green and red going to it. What is it? Thanks