1989 Ranger hood
 

Hey everybody. Just bought a 1989 Ranger with only 66200 miles. Everything works as it should and the truck runs great. The carpet doesn't even look like anyone has set foot on it. It has the 2.9 V6. There is what appears to be a factory made hole in the hood that has a small plastic plug in it. My question: what is the hole for? I can't seem to find any answers anywhere on the world wide interweb.

Have an image you can share?

I've got a couple of pics but, it's hard to see the plug.
https://cimg5.ibsrv.net/gimg/www.for...6b694f6a15.jpg
https://cimg8.ibsrv.net/gimg/www.for...6358e4cbf9.jpg

Up on the nose/ridge of the hood?