The glow indicator light in the dash of my '77 300D is not lighting, however the car also does not start. I changed all 5 plugs, the 50amp in-line fuse and the ground wire. Indicator still does not work and the car will not start. My next step is to check the relay, however I do not have an electrical manual yet. I know it's in the dash somewhere, can anybody help me out?

Second thing is that the plugs are all getting power. I'm under the assumption that if the relay is bad, power wouldn't flow to the plugs. Please advise.