A friend called my wife and said she had a" water in filter light " come on. and asked if I could change the filter she bought. The truck is a 1972 ford ( not sure if a 250 or a 350 ) diesel. Does anyone know where the filter is located? I'm working graveyard shifts until the first of the year, so my son may end up changing it. I do not have the truck where I can look at it. Thank you for the help. Joe