The real test on this system is to monitor the current flow during glowing with an inductive pickup. Resistance reading below one ohm are tricky. By measuring the current you are judging the dynamic system working through the real resistance with the effective voltage (the other side of the story).
That system starts at over 100amps instantly. The current drops as the plugs heat up to around 70amps. These plugs were called quick glow when they came out because they were designed to have very temp dependent resistance. Thus the high initial current and the quick reduction to not burn them out. The circuit should stay lit for 45 secs if no starting attempt is made.
If the current is down or if you can't measure this, measure the voltage at the fuse. The battery voltage shouldn't drop much lower than 11.5v during glowing.
I am actually guessing there, as I imagine your temp conditions are causing your battery to be lower than I'm used to seeing. I always wondered how you Yankees got them diesels going (bg), we have enough trouble in N. Florida. (three days a year). You have to have a hot battery to start a cold diesel.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
[This message has been edited by stevebfl (edited 03-20-2000).]