I have a 2004.5 lly that wont start, only throwing a "fuel rail pressure sensor low" code (working on that problem next) but before I ran any codes I put a test light on the glow plugs and they are not getting any power at all when the key is switched on. the light on the dash works(stays on long about 30s when its 80 outside), 175a fuse is good, good ground, 12.8v of power to the controller, but not putting anything to the actual glow plugs, do I need to replace the controller or check something else??

 

A freind has the same problem did you get it fixed and what was the problem