Clogged targa drain

Need to wash my new ‘86 328 GTS but the passenger side targa drain is clogged. There is currently some water down in it from the wash the dealer must’ve given it. I found out there was water when I ran a weed eater string down into the drain as far as it would go, which is about 19” from the drain, making the clog inside the A pillar. What’s the best way to unclog something like this?

 

I just tried a washing machine brush on a flexible cable. Couldn’t get it all the way through. Only about 12 inches in. Tomorrow a speedometer cable comes, I’ve read some have had luck with that. I’ll update. If it doesn’t work then my mechanic is going to fix it.
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I tried that with the trimmer string but not the metal wire. Assuming this is the hose? Seems like it’s hanging out a long way no?
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Ah so does anyone have a picture of the targa drain end?

 

Thanks!