Glow Plug Inspection, Remove and Replace
Inspection:
Good glow plugs are .5 to 1.5 ohms measured cold. The truck will throw trouble codes P1260 to P1267 when the plugs go bad. Typically the bad plug will read in the hundreds of ohms.
If you suspect a bad glow plug, measure its resistance:
-This is the glow plug controller situated between the battery and the master cylinder.
-Push down on the tab and pull the connector apart.
Connect one lead of the ohm meter to the negative battery terminal and measure at the indicated terminals.
Unless the wiring harness is on backwards (can happen), the glow plugs should be 4-3-2-1 (left to right).
Remove and Replace:
Warm up the truck so you have a hot engine.
Remove engine cover.
Remove the battery (10mm); you will need the room (you must, at least, remove the positive terminal to the battery).
To gain access to #2 glow plug, remove the alternator rear "T" bracket (13mm and 15mm).
Squeeze the black tab (red arrow) and unplug the harness connector to the glow plugs.
Flip the bracket out of the way.
Torque:
13mm M8 ( 9.8 ) - 12 ft-lbs
15mm M10 ( 10.9 ) - 14 ft-lbs
To gain access to #3 glow plug, you need to remove the intake elbow.
Remove the CAC hose (8mm).
Unplug the connector to the EGR Air Flow Control valve (FCV). The release tab pulls in the same direction as you need to remove the connector.
Remove 4 hex (Allen) bolts (5mm) holding the FCV to the intake elbow (see next pic).
You may need a tool like this to pop the bolts:
The FCV has a o'ring seal to the elbow that may need to be replaced.
Part #05142806AA.
It seems to be a 64x3.5mm Viton (70 or 75 durometer).
Loosen the clamp (7mm) on the EGR pipe enough to slide it off of the flange and down the pipe.
Remove the pair of 10mm bolts shown holding an electrical cable bracket.
Remove the (long) 8mm bolt at the far right.
Remove the (short) 8mm bolt hidden underneath that the arrow points to. This bolt runs parallel to the EGR pipe. And remove the (short) 8mm bolt above it.
Remove the 4 (long) 8mm bolts holding the elbow to the intake manifold.
I couldn't get my fingers on the inside front bolt and had to come from underneath. I will be re-installing it the same way.
Leave a couple loose bolts in the elbow and crack the gasket with a wood dowel and hammer. It should only take one small blow.
If you are careful, you can slide the elbow back and off of the top of the EGR pipe. You then won't need to remove the 2 bolts at the bottom flange of the pipe.
For re-install, the EGR pipe should have high temperature RTV Silicone re-applied (Permatex Red, or Orange as a 2nd choice).
Clean up the elbow and intake manifold that is accessible.
The new gasket to the manifold is #05066946AA (my dealer cost, Aug. 2012, $14.45!).
The 8mm M6 (10.9) bolts should be torqued to 6 ft-lbs
To gain access to #4 glow plug, remove the hose on the top left of the fuel filter and the two 13mm nuts holding the fuel filter to the firewall mount. Set the filter to the side.
Remove the glow plug connectors. They are tucked under on the side of the engine.
This plug wire has a white band indicating that it should be on the #1 glow plug (closest to the alternator).
Long pliers are required to get at these. The picture shows hose pliers with vacuum hose for protection.
Glow plug #1 is a straight shot so nothing has to be removed (except the battery if you like).
The glow plugs can be removed with a 10mm deep socket and a 6 inch wobble extension.
Put a rag around the plug and use a good penetrating oil/freeze spray to help when "cracking" it loose.
Heat expansion, rust and diesel goop can pretty much weld the plug in place so care must be taken in order not to break it off. Tighten then loosen the plug a few times to try to break it free.
The glow plug can be spun out with a section of 1/4" gas hose on the end of a rod or dowel. The next shows the hose on the end of a 1/4 inch extension.
Use a little copper anti-seize on the threads to make for easier removal next time.
This is a previously anti-seized plug that had 10 months of service extending through the winter.
Torque the glow plugs to 9 ft-lbs (12.5 Nm).
Reverse steps to re-install noting torque values and required rtv silicone.
Pump the air out of the fuel filter.
Oh well... New Etechno's seem to work good... 
