My cousin just bought a 96 C1500 with a newer 4.3 V6 (unsure of engine year, was told it was late 90's but much lower miles. Truck has 351k engine/trans has 150-175k). It's got a few issues but it's also a $1k truck.... that being said, I've figured out what's wrong pretty much everywhere but with the ignition. There's a black box under the ignition with, from what I can tell, 6 wires coming out from it, and the previous owner said he replaced it but it didn't fix the issue. When you turn the key, if the ABS light isn't on you have to hit the black box repeatedly until the light comes on, then the truck will start. Without hitting this box, the truck won't crank, and the electronics don't come on (fuel pump is on, but it's on a switch at the moment, not with the ignition, but the radio is off, while dash and dash lights turn on). Sometimes the truck is fine for a while once it's started (we drove it for about an hour with no issues) but other times it'll start then that little box acts up and the truck stalls, then I have to pull over and come to a complete stop and put the truck in park, hit the box till the ABS light is on, and then it'll start and I can drive as normal... truck will also not start in neutral, under any conditions. I'm thinking this little black box is bad again, but I have no clue what it's called... anyone know? If it helps I can add a pic of what I'm talking about...