I replaced the heater core and put everything back together. The truck is not getting any power and key is stuck. Battery has sparks coming from terminal so it’s not the battery. Replaced relays and still not starting. Any ideas?

 

Did you unhook both battery terminals? When you say no power, nothing?

 

the positive was unhooked while the vehicle was being worked on. Both of the terminals are on now but no lights, and the ignition won’t turn and the key is stuck.

 

How much did you have to tear apart to do the core.

 

everything forward of the front seats..yep

 

the whole dash steering. It’s behind the stereo and everything.

 

yes. Changed the the relays and still nothing.

 

I pressed the spring to get the key out but I still can’t figure out why it’s not starting.

 

Not cranking, or not starting? I'd suggest with a test light or voltmeter, look at the ignition/crank circuit. This sounds like it's a point to point voltage check, and eliminate process.

 

connector not plugged in?