I posted this before but must have put in the wrong place or just can't find it. I have a cold weather starting problem, my fuel heater/pre heater or whatever it is called is not working. Where would be the place to start looking for the problem.

 

Sorry I left out some information about the truck. 1997 Ram 3500 Cummins 12 valve

 

Grab the 96 service manual from the faq section here, there are wiring diagrams that will help you with finding where the issue is.