1st gen ranger dash dummy light question

[1986fordranger]

hello , yesterday i was looking at my two dash gauge clusters , one is from a 1987 and one is from a 1986 , and both of them have a black plastic cover that is glued over the light bulbs for the dummy lights , and both have the normal , check engine , check oil and seat belt , rear antilock , brake , and 4x4 and low range lights , surpriseingly there are resurevations for the following dummy lights (just no bulbs for them ) , emiss , and water in fuel , i'm guessing the emiss is for (emissions) ? , but the real thing that i don't quite understand is the (water in fuel) light ? , was that only used on diesel models ? or was there a dealer installed option for gasoline models too ? , thanks for any clearifycation on theses questions , heres a link to a photo i have of the cover http://www.mytractorforum.com/album.php?albumid=1684&pictureid=6425 , shows what i'm asking about , thanks

 

[hondaxr650]

Water in fuel would be for a diesel.

 

[jhammel85]

Definitely for Diesel.

As far as the other ones go, Are there actual prongs in there or just bare plastic? All of mine that don't have bulbs, have just plastic. No metal prong.

 

[85_Ranger4x4]

Mine is about to lose the bulb for the emissions light...