My truck threw Code P0674 so I guess I have to change #4 glow plug. How hard is it to change the glow plugs on these trucks? Also, how do I know which cylinder is #4 cylinder? 2012 F250 CCSB 6.7 20's, BFG AT's, 3.5" Readylift. 7.3 Powerstroke 4 inch downpipe to 5 inch mitre cut stacks Southbend Dynamax clutch DP Tuner 2006 F-450 6.0 Bone.. 6.0L Power Stroke Engine and Drivetrain P0674 Glow Plug Cylinder 4 Circuit. Jump to Latest. If test light lights on all 4 pins, you have an open in engine harness or bad GPCM, you will then need to find the #4 glow plug pin at the module and use a test light to see if it will light on the #4 glow plug circiut-if it lights, this verifies.
![[DIAGRAM] 6 4l Powerstroke Engine Diagram](http://ww2.justanswer.com/uploads/AU/Autotech58/2013-01-14_030409_151-9.jpg "[DIAGRAM] 6 4l Powerstroke Engine Diagram")
Absolutely the only glow plug I trust on these engines-http://www.amazon.com/gp/product/B001CA550M/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASI.. Easy way to remove glow plugs on a 6.4