You can maybe post something on local marketplaces. Something like Kleinanzeigen (Germany), Facebook Marketplace (US I think) or something similar.
Or local groups.
There are a lot of hobbyists who have a printer that stands still for 99% of the time, who can print it for cheap.
Or, as someone else already has suggested, your local library.
Just be sure they can print in the desired material. A part for a car is going to need to be resistant to heat and potentially UV in ways that the most common material, PLA, is not.
Where are you located, as in what country? That will probably change the answer a lot.
I would advise finding a local nerd to print it for you rather than using a commercial print service. For functional parts, it may take multiple attempts or some fiddling to ultimately get it right, which is going to be a massive pain in the ass if you're ordering parts by mail and paying for each one.
A local individual is a good idea, unfortunately I live in a very rural farmland area, not many "local nerds" to speak of. But I could do some traveling.
There's a very popular YouTuber that does his 3d printing on his goat/sheep farm in rural Sweden (I think that's where). Point is, you don't know who has a printer. I personally drive around a lot for my work and would certainly be willing to drop something off if you're in Indiana and I can. Just post the nearest bigger city and see if anyone responds.
For use in a vehicle I would definitely recommend printing out of ABS at minimum (which is what most OEM plastic car components are made out of anyway, at least the ones I've looked at in my life that were marked as such on the back), so you'll need someone who can do that with their machine also. PLA and probably even PETG will deform in a car sitting in the sun.
I'm probably not local but I am a nerd, and my machine can indeed print ABS. Post the file and I'll take a look at it?
I would try local library first, then your local Discord community, and then maybe Nextdoor.
I know Nextdoor can be a real shitshow of paranoid street watchers and bad political takes. But I have found it very helpful when it comes to stuff like this (and getting recommendations on local services / shops in general). Be sure to say you have the STL and are willing to pay a reasonable amount for help with it.
Is buying a 3d printer cost prohibitive? If not, this might be your time. Even if you tell yourself this is probably the only time you'll ever need anything 3d printed, I bet you'll find yourself printing all kinds of stuff. I think every household should have a 3d printer. You can geek out with them for sure just like you can with cars or brewing coffee, but they can also be useful and fun for everyday users like coffee and cars too. Nerd level knowledge is no longer necessary for entry.
Unfortunately a 3D printer is not in my budget. I could afford one, but it would come at the expense of some upcoming costs I have to account for. Maybe in the future when I have a better living situation it would happen! I have always wanted one. It would be fun to mess around with.