TheDieselStop.Com is a source of information, discussion, and help pertaining to the full line of Ford trucks, SUVs, and vans with International diesels. We cover everything from the original F-250s with 6.9L diesels all the way up to the newest 2008 Super-Duty trucks with the new 6.4L Power Stroke engine.
The best tool for glow plug testing is a standard +-30 Amp ammeter. Glow plugs can fail in one of 2 ways. Either short or open.
Testing glow plugs with an open a continuity meter or Ohmmeter will work, but not if the glow plug is shorted. A shorted glow plug will pass current but it won't get hot, at least at the tip. When a resistive heating element gets hot its resistance goes up and the current flow for any given voltage goes down. When you put the ammeter in series with a glow plug and activate the relay the current will spike to about 40 Amps and decay to about 15 Amps over a 3 to 5 second period. If it's shorted the current will just go to 40 Amps and stay there because since the current is not flowing through the element (shorted at base of plug) heat build up doesn't occur and current doesn't decay.
6 inches of AWG #12 wire and standard male/female automotive bullet connectors is all you need. Also always replace glow plugs as a complete set not individually. As glow plugs age heat output per given current flows change. Replacing individual units will lead to cold jug starts (rough with white smoke) and generally harder starts in cold weather.
'05-'06 High Idle by StuartV Great instructions how to modify an '05-'06 upfitter switch into an AIC.
6L Shootout Reports by Ralph Landau Results and conclusions from Ford 6.0 Liter Shootout held on 9/3/2005 in Nashville.
1999-2004 $10/$15 AIC by Rob Milnes Rob Milnes walks us through building and installing a $10-15 AIC on a late-model Power Stroke.
Ceramic Coating by Clive Buttrey Clive Buttrey (cbuttre835) explains do-it-yourself ceramic coating on his 1997 Power Stroke.