1997 Chevy C2500 5.7 Vortec

Weird issue that I'm hoping someone can help me with.

The IGN A 40amp maxi fuse keeps blowing every time I turn the key to the On position. I tried pulling the connector from the camshaft position sensor, map sensor, etc and nothing changed. I even tried disconnecting the starter and it keep popping the fuse.

Finally figured out that if I pull the "Eng 1" mini 20amp fuse, the voltage goes away and the 40amp fuse doesn't blow. The 20amp Eng 1 fuse never pops in any of these scenarios.

If anyone has any ideas, I would appreciate it. I'm not the best at troubleshooting something like this.

 

I'd recommend getting a Hanes manual or something with electrical schematics, and a multimeter. See which components are connected to the IGN-A fuse, and which ones have the ENG1 fuse in common, and that should give you a clue where your short is.

http://www.bbbind.com/tsb-wiring-diagrams-database/