1978 924
Voltage stays steady at 13 volts. When I turn my lights on going home at night my voltage drops to 12 . If I stop and run at idle, it drops into the red and fuel pumps slows.I started changing all the grounds, battery to body -body to engine.The car is a week old to me so I am still getting the bugs out.
Alternator ground is next but I hear this going bad is rare.

I also noticed the air scoop on the alternator and the plastic air tube near the radiator which points down toward the alternator. Am I missing a hose between the 2? Thanks for the help. I only got 2 good days out of the car but I am still all smiles.

 

Take it to your local auto parts store and ask them to test your charging system. It appears the battery isn't holding much charge and/or the alternator isn't putting out enough amps. If they check out OK, look for a short in your lighting system.

There should be a hose to cool the alternator. I found a flexible air intake tube (2.5"?) at the local AutoZone that fit.

 

thanks for the help/ its a new battery so its probably not that.
Does the hose mount to the grooves in the scoop or am I missing some sort of clamp
Thanks again