I've done hours of reaseach before posting this thread, but I still need some advice.

Sometimes, my car will not start and the glow plug indicator light does not come on. This seems to happen after the car has been sitting for a week or so. But the starter always engages. I have to turn the key on/off several times for the glow plug light to come on and then the car will start and run normally.

I can get this starting problem whether my car is cold or at normal operating temperature.

Here's the symptoms when I have this problem...

turn key to on:
no glow plug indicator light
auxillary fan in front of radiator comes on after approx. 5-seconds (fan does not come on, with the key in the on-position, when the car is acting ok)

turn key to start:
starter engages normally but no engine fire

I have a few theories I would like to run by you...

Bad temperature switch or sender causing the aux. fan to come on and the glow plug light not to illuminate and the car not to start?

Bad iginition switch?

Is there an OVP relay on a diesel that may be bad?

Bad fuel shutoff valve? Why would that make the aux. fan come on when the key is on (car not running) and the car is cold?

I don't think it's a bad neutral switch because I think the neutral switch will disengage the starter and my starter is not giving any problems.

Please let me know your thoughts. Thank you.

__________________
Neil
1997 E300D - naturally aspirated
280,000 miles (as of November 2015)