My CUCV will start in 13 degree weather at a bump of the starter. I run AC60G's and I have gotten rid of the resistor behind the air cleaner housing and routed the feed wire to the 12V bus bar as outlined in the Doghead Bypass sticky. I went through the headache of removing swollen plugs 2 times prior to following the advice being offered here but the truck has been equipped this way for over 4 years now and I'll bet it'll start right now in Georgia's cold 20 degree weather at the moment!!! The original system with the resistor pack works fine so long as the resistor is good and all 8 glowplugs are in good shape. Let one drop out, the rest see 14 volts, 2 drop out, the rest see 16 volts and so on they burn out in short order once the first one goes. The glowplugs for these trucks are 12 volt, let them have 12 volts!