Merci beaucoup messieurs for all your suggestions! Thankfully, there was no water leak, stinky carpet or carpet padding to deal with.

After trying various methods for deodorizing the beast, I discovered that some little rodents had made a home for themselves above the hood insulation. Removing the insulation and cleaning the area has solved the problem!

I do like the vinegar idea! That's one I hadn't heard before.

FYI -

Peppermint oil, such as found in peppermint Altoids, is supposed to deter mice as they hate the stuff. Needless to say I now have some under the 2 front seats...:)

Check your 240 air filter boxes periodically. I once had mice make a home in there.