I have a 1994 3500 with 6.5 turbo I started having a problem with glow plug not cycling rite when I first turn on it used to cycle glow plugs . now the lite comes on for a second then goes out keep waiting for 20 sec it cycles and starts ok . any ideals ?

 

glow plug relay wearing out. new one needed. wouldn't hurt to change GPs also

 

already replaced all of that I was thinking possibly computer problems

 

Coolant sensor in water crossover AC Delco?

Grounds at rear of intake clean and secure?