Hi Guys

the coil symbol in the dashboard of my 2003 w203/cl203 c220 CDI coupe car is constantly turned on

does that mean that one/some of my glow plugs is/are defective? i can still start the engine in cold morning with no problems

if they are i am thinking of changing them myself but is there a way to actually identify which glow plugs are not working before physically removing them and then testing each separately? like some hidden option in teh dashboard

or could this be an electronics glitch? sometime i get these weird electrical errors that disappear after sometime, however, this error (the coil symbol) has been on for some time now 4-6 months

your help is appreciated

Haitham