Mr.Ernie

Hey everyone, I'm a first-time poster here, but this isn't my first tango with a GM truck. I just bought a 1996 Silverado C1500 with a 502 that wasn't running for a few hundred bucks. Buddy I bought it from said all it needed was a starter, so I thought it a decent gamble since a refurb starter was only $150.

Having sat for a few years, the battery was completely drained. So after loosening up the engine and putting on a Champion refurbished starter, I connected a new battery (all parts are specific for this truck, proper starter and proper battery) and the engine started turning over on its own with no key in the ignition.

This leads me to one of two conclusions. Either theres a short between the positive wire that goes from the battery to the starter and alternator or the ignition relay is fried. So my question is two-part. First and foremost, am I wrong? I'm by no means an expert, just someone who likes to get dirty in his driveway and loves GM trucks. My second question is, if it is the ignition relay, where is the relay switch? Any advice would be great, I need to get this thing rolling so my wife can have the car back, haha.

Thanks in advance!