Hi all new here, I have a late 2001 ML270D
When you turn the ignition to on the glow plugs activate for 10 to 15 sec which I think is normal, after you start the engine the glow plugs reactivate for abort 50sec to 60 sec this has just started to happen,
Does anyone know what might cause this and how to fix it?
Thanks

 

The glow plug light not only indicates that the plugs are energized but acts as a trouble light also. I had a similar situation on my 93 300SD. I replaced all 6 plugs as my car was 17 years old when I purchased it. The problem could be plugs or relay.

 

93mbw, Thanks for that,
I will see if I can test them. I can't find whitch relay it is?