Hi,
I'm slowly working down the multitude of issues with our Libby CRD. It has been hard to start this winter but I did not have any glow plug related codes. With 71k miles on the odometer, I replaced the glow plugs and the wiring harness. It was 10.5 deg F outside and I did not garage the Jeep so it would get a good cold soak. The glow plug indicator light flashed on for about 2 seconds and I then waited another 3 seconds (takes while for Kennedy lift pump to spin up to full speed) and the engine fired up almost instantly.

So, based on my experience, if you have any difficulty starting, it may behoove you to replace your glow plugs. Also, check resistance of each terminal/wire on the glow plug harness and if you see anything unusual its worth the 44 bucks to replace the harness for peace of mind. On 3 of my terminals on my glow plug harness, I had virtually no resistance but on the number 4 glow plug, I had .3 ohms resistance. I also had insulation on my glow plug wiring harness that was damaged and showing bare wire.

If ANYONE in my local Colorado area 1-2 hour drive from my home needs help with glow plug removal/installation..just holler. Removing the AFCV and intake tubing to get to the number 3 plug is a PITA but now that I've done it, I can probably do it 1/4 of the time that it took me to the 1st time. Also, I can also help with EGR removal and replacement/cleaning. The EGR valve is not difficult with intake crap removed. The hardest part about the EGR valve assembly was removing the EGR coolant hoses. I ended up cutting mine and putting new ones because my old ones were damaged from the &*(*&^%^& oil leak that I have coming from the "valve" intake manifold gasket.