Water leak inside A-pillar passenger side?

I've had previous issues with water leaks.

I had initially taken the car to the dealer for repair because of the headliner leaking water. A year later after heavy rains same issue. Took down the headliner and 2 of the drain lines were disconnected and could tell it had been leaking for a while. What I didn't realize until later is that the drain tray has probably been leaking since being manufactured. So, I would rather fix this myself, I'm not very trusting of the dealership fixing issues correctly and not breaking something else (and yes, I've experienced this a few times before).


Leaks have been addressed as follows:
Under cowl has been sealed.
Moonroof has new drain lines put in (had come lose), moonroof drain tray was also sealed (had issue with leaking).
Moonroof has been taped up to exclude in troubleshooting leaks.

Viewed on YouTube removal of right front fender and didn't see any seams that might be a place for leaking, it was an HHR but not sure if it was same year (was hard to find and only video found).


Situation Now:
I have a water leak inside the passenger side A-pillar, have used a mirror to view up inside the A-pillar and see a seam about 2 to 2 1/2 feet up where the seam is leaking and running down the inside of the A-pillar.

The windshield has a plastic trim (semi-hard plastic) on each side that doesn't appear to come off, unable to remove to see if it is leaking there.

Water leaks down from inside the A-pillar pooling under floor mat. Car just sitting in driveway under heavy rain.

Have used soapy water around windshield with blower on high and doors closed.

Can see some bubbles around door handles outside (understandable) but no indications of leak around windshield.

I don't believe the car to have been in any accidents, bought used from a chevy dealer in 2014.

At this point I don't know how to get to the leaking seam.

I can't find a good diagram of the A-pillar in relation to the windshield and if it's possible to be leaking from the windshield into the A-pillar.

I think I may be incorrect in my reference to the A-pillar. What I was calling the A-pillar is the enclosed column in the body structure that the passenger side door is bolted to that I believe now to be the structure that runs into the A-pillar. I'm not sure now how to reference it and didn't want to lead you astray. That column between the floorboard to the A-pillar

Any help you can give would be greatly appreciated.

Regards,
Dennis