914-6 Gen light comes on when hooking up the battery. Options

[Porscheman912]

Ok, I have a friends 914-6 here, and just built the engine in it. Before doing the engine, and after, the Gen light comes on when the car is off. I took the starter, and Alt to a shop to have checked out, and they were both good. Replace the Volt reg with another new one I had, and still on. I have a wiring diagram, but does not show wire colors, or switches. The light would go out in 2nd position on the ignition switch, and then come back on. I dropped the fuse panel down, and now it is on in all positions. It goes out when started. I was getting a very light arc when I hooked the battery up, but when I unplug the alt plug from relay board it goes out. I am thinking it may be the ignition switch itself, and just wondering if anyone has seen this on these cars? It is an OEM 6, not a conversion. Any help would be great, I need to get the owner his car back, and I am still testing things, just trying to save time if someone else has seen this.

[Porscheman912]

Ok, I think you are right about the diode. Now that I have the alt out, I checked the wires, which tested good. Anyways, this morning, I grabbed another alt I made some jumper wires, and hooked up the alt. It was out of a 70 2.2 911, so everything had to be different. So, and electrical engineer friend of mine was out, and explained that even though the diode might test good, it could be bad under a load, due to leaking. He told me that it is like one way valve, electricity s suppose to flow one way out of it, and under a load, it may be leaking a just enough. I left the battery hooked up for 8 hours, and it dropped .8 volts. Thank you to you all for your help, I have never seen this before, but I will always remember it.