Mercedes-Benz 300D-T

1985 Mercedes-Benz 300D-T Ignition System   

My car will not start. The lights, radio work, the glow light, lights up and then turns off that is when I turn the key and nothing happens

The first thing is to make sure the battery is fully charged. Do the headlights come on bright?

If the battery okay, start by checking connections at the battery/starter/alternator/ including the battery cables. Don't overlook the importance of this.

If these are okay check for voltage at the small wire to the starter when the key is turned to the start position. If voltage is available at the small wire the starter should be removed and tested. Most chain parts stores will check this free of charge.

The lights are bright, brand new battery, connections good. do not know about the others because it is dark and had to be somewhere, but now it starts. Because I have only had this car since May,it is my first Mercedes, it could be alot of things.I do not have a MB manuel.just recently the single lights didn't work and I panic, took in to hear a wrong dig. it was a button on my control panel that voids the single lights,didn't know about that. So I don't know now but its been running like a champ no problems ever starting

Had the car been sitting without the engine being started for a while?

come on folks the answers here are lame, I said my car was running like a champ I drive 50 plus miles every day 7 days a week, If a car doesn't start any idiot would look first at battery which I stated was brand new, lights ect work awsome, next one would asume the starter ect please does anyone know anything about MB late models they are not Fords or Cheveys

The starter interlock is the next common failure. Sorry for pointing to the basic failures first, but they cannot be overlooked regardless of make.

I'm unclear, was this a one time problem or does it persist?

Has the starter actually been tsted for current draw etc.?
Starters have brushes and contact points on the armature that commonly wear and cause lots of current draw.
MB starting systems are still a basic system that is the same as all others.
A 24 year old MB starter would be suspect, and worn brushes/armature can certainly be erratic.
Running a 'jumper wire to the starter solenoid would eliminate other variables and point to a starter problem.
Douglas's suggestion for checking voltage at the starter is quite valid.
No matter how cold and dark it is you still have to do the basis electrical diagnostics.

1983 Mercedes-Benz 300D-T Heating / Cooling System   

no heat. (A/c does not work on this car.) No power to blower motor. Fuses are good. Blower motor works fine when hooked up to power source. Considered getting new motor but don't see that solving the problem. Is there a relay on this circuit? If so where? I am thinking that maybe the A/c not being charged has something to do with it. But it has not been charged for years and the blower still worked. I am stumped.

It could be the switch or relay, look for a relay block (you may be able to hear the relay click or it may click if you wiggle/squeeze it when the key is On blower On High). Don't overlook the connector to the blower motor. If you need more information on this I'll see what I can find on it tomorrow (info can be hard to come by on these).