[>:]well if anyone out there knows what those plugs are that have a 19m.m. head on them with wires stickin on them please-share the knowledge- there location is above the actual glow plugs about 3 inches-thanks- [:'(]- and i will let you know about the glow plug swap plus relay- [8D]- peace-[X(]ohyeh its a1980 300d mer benz old school tank

 

Take a look at this free service maual at this site look atpage 2 and especially 3. It it is a big one with 2 wires it is the temp. pickup for youf glow plug timer when it gets hot enough it makes sure your glowplugs are off.
http://www.pauldrayton.com/uploadfil...615/05-100.pdf