I read most of the info on here and it guieded me to the following:

I had them replaced with the 7v ETecno glow plugs a couple of weeks ago. I no longer have any codes, but the system doesn't seem to do anything. I live at 9,000ft so I still have cold mornings and we had a lot of snow and cold temperatures last week. The glow plug light doesn't come on from what I can tell, and it takes a considerable amout of cranking in short bursts (around a dozen or so) to get it to fire and stay running so I have to plug it in every night (probably low to mid 30s this week). Not a problem plugging it in at home, but will be a problem next winter.

What should I check to see if the system is working? Where is the control module located? Are the 7v control modules still available anywhere?

I (well my X) was pretty lucky on this (bought it back from year a couple months ago. The #1 glow plug tip broke off last year. It passed without destroying the engine or turbo. I was shocked when I saw the glow plug.