What bulb size goes under the hood? Auto Parts stores can't tell me.

It's been empty since I've had it and I'd love to put an LED in there.

What year?

97 Country

Assuming the '97 is the same as a '00 you need a 561. You also need to find another auto parts store. I work in one and can find it in the computer. And I am not even a counter guy. I just deliver the parts.

https://www.napaonline.com/napa/en/p/LMA561/LMA561_0238030230

Not surprised you couldn't identify it from the vacant light unit, it is, to our eyes, a peculiarly American fitment BUT, yes there is an LED equivalent; I got a couple last time I was over but can't remember where -try usual suspects, AZ, O'R's, etc.

Reminds me, must pull the cover off my latest to see why it doesn't work - but that's a '97 & it looks same as my '99, if that helps.

OK, so checked mine today & - no bulb!

Couldn't find the spare (just one of severeal I have) so pulled the one out the '99.

That was out of a Seville after fitting LED; now according to NAPA the underhood light for both vehicles, the Caddy's trunk light & the Cherokee's cargo light all use the same bulb - but the ones in the Caddy ARE different (like a fat festoon, but with a saddle across the end caps). They'll fit - with a struggle, the 561 will be much easier & you won't risk the fuse, if you forget to unplug the light first.
However, I would recommend in your case, pulling the lamp & giving all the metal bits a good clean. Oh, & toothpaste will transform the lense!