[franken]

Since there's an almost identical thread, I just pasted my post from the other.

There are believers in the idea that hundreds of millions of GM vehicles used the same starters and wiring and they worked, which they did, and there are those who don't.
Fix the underlying issue and the solenoid will work. Typically, the underlying issue is bad wiring and/or poor connections, or worn out (resistive) switches in the circuit.
Of course, a bandaid solution is easier than troubleshooting so it's popular.
Yes, it's a bit of a long path from the battery to the solenoid, but I've jumped solenoids with a 20G or smaller jumper, so it doesn't draw that much.

Measure voltage to the block and to the battery from the S-terminal.