Thanks - jkoebel - for the quick reply. I will try your suggestions. This is for a 1987 300 D Turbo. It might be similar though. Pencilglow plugs, not loop type.
My maintenance CD says in step two- after verifying the dash indicator lamp was good states;
" If the glow lamp is in order, test the black cable from connector contact 3 of the preglow time relay to the preglow indicator lamp for interruption. Rectify interruption. If the preglow indicator lamp lights up, the preglow time relay is faulty. Renew preglow time relay."
I do not understand this test. An help would be great.
I have a test lamp and a cheap digital multi meter.
