Here is the situation. I have a 1990 Mercedes 500SL and is is currently not starting.

I had driven the car with no problems all last year and parked the car for the winter, but forgot to disconnect the battery and the battery drained completely.

Installed new battery and it will not fire, no cranking whatsoever. The battery is fine, as well as all the fuses.

Any suggestions ?

Corroded ground strap? Have you done an amperage draw test on the 2nd battery? Maybe it too is discharged. I have seen it before.

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Doug

1987 300TD x 3
2005 E320CDI

Installed new battery and tested, it is fine. All in grounded properly as well.

I also checked the overload protection relay fuse and that is not blown. Any other suggestions ?

Tempting the obvious : Have you tested the starter? Do you have power otherwise (ie windows, radio and stuff works?)?

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1989 300E 144K

I have not tested the starter no, but i cannot see this being the problem as it was perfectly fine prior.

I have all other functions that the battery should produce yes ( lights, horn, etc. )

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Either or both ?????


Try "N" position on shifter...............

No cranking at all and no sign of it even trying to fire. I tried starting it in N and still nothing.

maybe the ignition switch ?

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Well , if it does not crank, then it certainly can't attemp to fire ...that is what was confusing about your complaint.
Your complaint is the car does not crank, meaning the starter circuit does not engage.
Do the dash lights indicator lights come on when you turn the key to RUN position?

Yes, all of the indicator lights come on in the run position

On the W123 diesels there are easily accessable terminal block that can be jumped across so the motor can be turned over from the engine compartment while adjusting the valves. Maybe the W107 has the same feature? This would allow you to bypass the ignition switch.

__________________
Doug

1987 300TD x 3
2005 E320CDI

Do this bat cable/terminal test:

Turn on headlamps.
Turn key to Start position while you or someone watches headlamps.
Do they stay lit when key is in stat position??????????????/

I'll try that later this afternoon whne I am at the car. What will this tell me ?

If the starter solenoid is getting power it will draw amperage and cause the lights to dim significantly. If they dim, then the starter or solenoid is bad, or frozen.

__________________
Doug

1987 300TD x 3
2005 E320CDI

It tells you if the cables or bat teminals have a poor connection under LOAD
[ caused by starter motor draw/load] ..it is just a quick tech trick before we go into wiring circuits.
Just for info, You have a 129 chassis

Sorry for stepping on your post Arthur. Won't it also tell you if the starter or solenoid are bad?

__________________
Doug

1987 300TD x 3
2005 E320CDI