I have an '04 GT1 GP and I've also had a similar issue with the windshield washer fluid indicator on my DIC so I checked it out. I noticed that the level was low enough that I could no longer see it and in a couple days I ran out of fluid. I filled it back up, but the low fluid indicator didn't go away. I was stumped. It was so full that I could see it at the top! It was by no means low. Dealt with this for about two weeks, then started looking for a replacement sensor... didn't really want to spring for it because installation looked difficult and it wasn't worth the money for the sensor because it really wasn't hurting anything. I found out where the sensor was located (up in the passenger side of the bumper) and beat the crap out of the sensor and pushed on the fitting for the plug to make sure it was connecting fine. Surprise, a day or two later the problem went away and it's been a few months and it has not resurfaced!
Here is the part for my car, should be the same for yours not I'm not completely sure! about $22 at rockauto RockAuto Parts Catalog
