Having car issues, need help

First post here, been a frustrating couple days trying to look for information online, so finally broke down and went to forums.
Started about 3 weeks ago, truck would need a jump every now and then. Replaced battery, wouldn't turn over, figured it was the starter so replaced that.
Now it won't do anything... fuel pump comes on, radio comes on, but not even a whirring from the starter, alternator checks out good. I thought it might be the aftermarket KARR Ex-1 that the dealership installed for some reason, but I can't find where it's spliced into the starter wire, and there's no valet switch like it says, so I'm at a loss as to how to go about fixing this, any help would be appreciated.
2004 Chevy S10 ZR5

First post here, been a frustrating couple days trying to look for information online, so finally broke down and went to forums.
Started about 3 weeks ago, truck would need a jump every now and then. Replaced battery, wouldn't turn over, figured it was the starter so replaced that.
Now it won't do anything... fuel pump comes on, radio comes on, but not even a whirring from the starter, alternator checks out good. I thought it might be the aftermarket KARR Ex-1 that the dealership installed for some reason, but I can't find where it's spliced into the starter wire, and there's no valet switch like it says, so I'm at a loss as to how to go about fixing this, any help would be appreciated.
2004 Chevy S10 ZR5

I would get a voltmeter and with a helper find out where the power loss is. a good place to start is the fuse box. also make sure fuses seat into the sockets securely.

how did you check the alternator ? starter ? power to the starter ?

if this has some aftermarket anti theft device that could very well be the problem since most times the people installing these devices do not use solder and approved wire connectors. good luck.