I have a 1999 Chevy blazer, and I started having wiring issues about 2 weeks ago, and it stopped starting so I could not drive it. I took it to a shop and they couldn't find anything. My blazer will now start, but when the key gets to the on position, it tries to start itself. And when I have it in drive or reverse the starter stops cranking. But as soon as it is put into neutral or park, the starter keeps cranking. And it won't stop until I change gear, or shut my truck off. And sometimes when the blazer is off, with the key out, it tries to crank and roll over to start itself. And I recently noticed that when it's off, there is still power running my blower motor, and my 4x4 button light. If anyone can help me please..?? I have no clue what to do

 

Can the ignition switch be bad? They are a mechanical part that can wear out after 20 years of key chains hanging on them.