I have a 1998 H3-45. During the last outing, I seemed to be having an issue with the functioning of bay and engine compartment lights. It turned out that the issue was just with the engine compartment lights.

I started searching for a stuck switch and couldn't find it. I started using the breaker to shut down all bay lights which also shut down the engine compartment (EC) lights. I also used the bay lights defeat function on the dash panel. However, neither of these was very convenient.

After studying the EC for a bit, I found, on the frame post at the rear passenger side, these (gloss black) bolts with wires into the back of them. I called the tech and asked him if these were related to the issue. His comment, "probably". They are reed magnetic switches. Well, low and behold, the magnet (3/4 inch round and 1/4 inch thick) on the side EC door had fallen away.

These magnets are applied with an adhesive whcih apparently dries out and fails. You might want to check those (one on the back EC cover and one on the side EC door) as this is an issue which is not apparent and does discharge batteries.