Engine Electrical:
Battery Safety
http://www.peachparts.com/shopforum/diesel-discussion/141479-battery-safety.html#post1057827

Is starter health important to your diesel?
http://www.peachparts.com/shopforum/diesel-discussion/107318-starter-health-important-your-diesel.html#post739798

Battery selection / Charging System / jump starting / cold weather battery issues
http://www.peachparts.com/shopforum/diesel-discussion/141516-battery-selection-charging-system-jump-starting-cold-weather-battery-issues.html#post1058189

Glow plug testing.
Glow Plug Testing?

Symptom of 1 or 2 bad glowplugs...
Symptom of 1 or 2 bad glowplugs...

Don't always trust your glow plug indicator light!
Don't always trust your glow plug indicator light!

Glow Plug Relay
Glow Plug Relay

New Glow Plug kit installation. 1978 240D
New Glow Plug kit installation.

Glow plugs link thread
http://www.peachparts.com/shopforum/diesel-discussion/137732-glow-plugs-link-thread.html#post1019018

Replacing Glow Plugs
http://mbdieseldiy.tripod.com/glowplugs.htm

Note: the following link is for a W115
Glow plug timer relay location
Glow plug timer relay location

reference sensor on a diesel
reference sensor on a diesel