Glow plug relay issue

[heritagewraith]

Good morning. The original relay was clicking and in the start mode of the key the engine was cranking. The relay had stopped clicking. So, I figured that is had faulted. I purchased a new one, installed it. The new one does not click (cycle). The key in the start position does not engage the starter. I push in the clutch, I have full power (volts). I release clutch, I have 8-9 volts. I only have one battery hooked up. I read somewhere that I need both batteries. The blue wire has no power. I just recently purchased this truck. It has been sitting for about 3 years.
It seems as though that I might have several issues that are occurring.