Okay guys so I have a 1969 olds cutlass we restored. When we got the car we wired something wronge because I'm getting a parasitic drain on the battery. When I take the wire off from the horn relay to the firewall the drain goes away but also the car won't start or turn on. We have a wire from the battery to the alternator and then a wire from the alternator to the horn relay. Anybody have any suggestions on what that wire feeds from the horn relay to the firewall and where it could possible be grounded at? It's a bigger wire. Thanks in advance!

And if you pull every fuse and the draw is still there disconnect the red heavy alternator wire. If the draw is gone after disconnecting that wire you have a bad diode.