Code P0410 after replacing air pump several times

I bought my 2001 Grand Prix with a 3.8 liter (non supercharged) earlier this year. Within the first month, the check engine light came on with a P0410 code. Took it to the shop here at the auction that I work at to get repaired. He ran the diagnostics on it and found that the air pump wasn't working. He pulled it out and it was full of water, due to the air inlet being so low. So, he replaced the air pump and re routed the air inlet so that it was higher up into the engine compartment. That same night, the light came back on, so I brought it back in the next day. The relay failed and popped the fuse. Replaced both, and the light was off for a full day.
Got ready to take it in for its emissions test today, and the light came back on again. The air pump is not working, again.
Turns out that the previous owner had replaced the air pump twice (once with aftermarket, and once with an OEM unit) because of the water build up and freezing the first time.
I am not aware of any GM service bulletins, but there has to be something that is taking out these pumps. The only things not replaced on the secondary air system is the lower check valve and solenoid.
So, what could be causing the pumps to fail prematurely?

There was a TSB on this, but I don't know if it applied to your year vehicle....

There was a problem with the inlet hose allowing water into the pump....the pump freezes, causes the fuse to blow......new pump and hose(installed in a different position) usually took care of it.....

But this was done and it immediately re-happened?

Did the new pump have water in it again?

Was the outlet hose cleared of all water?

The light came back on the very next day after we had done the relay and fuse (air pump was done one day prior) when i was on my way to get it tested. He did the inlet reroute so that it is in front of the battery, and did clear out the water from the lines.
He is a GM Certified Mechanic, so i am not not worried about his abilities. I'm just under the educated assumption that something it shorting out the pumps.

There are only two things that can short that fuse.....the pump is seized(frozen water), or the harness to the pump is chafed.......

So what I am asking you is this.....when you start the car, first thing in the morning, does the air pump come on?

If it doesn't is the fuse blown? Is it getting power AND ground at the harness?

If the pump runs but sets the code, then you could have a bad solenoid valve....

This is easy to check out with a scan tool......there are two things you can check.....there is a pressure sensor in the solenoid.......so what you look for is does the pressure change when the pump runs, and does the O2 sensor go lean when the pump is running......if they don't, then it's a good chance the solenoid is not opening or is restricted with carbon.....

The first step is does the pump run, when when the car is first started......it will run for a specific amount of time, based on coolant temp data.....so naturally, starting first thing in the morning will be it's longest running time, especially in the colder months......once the car is at normal operating temp, and you shut it off, and then restart within a a few minutes to a half hour, that coolant will still be hot, and that pump, may not even run, and if it does, it will only run for a very short time....

I just checked it, as i haven't started it all day yet, and it's only in the lower 40's here today, and i did not hear the pump power up. Willing to bet that you are right with the damaged wiring harness.
Thank you, and i will follow up in a few days with an update