1985 Mercedes Benz 300sd Mercedes 300sd ignition problem

SCOTTHOMAN

MEMBER
1985 MERCEDES BENZ 300SD

Electrical problem
1985 Mercedes Benz 300sd Two Wheel Drive Automatic 279164 miles

Turning key to "Start" does nothing. All I hear is a relay in the dash making a clicking sound and that may be when I turn the key to "Run" which is before "Start." I have not changed any parts on the car. It started thousands of times without a problem prior to this. The battery still shows 12 volts roughly. There is no click from the starter or the selonoid. I am thinking of taking a closer look at the starter electrical connection but from what I saw when I crawled under there I didn't notice any obvious problems.

Does this car have a relay between the ignition switch and the Selonoid? If so where is it? I have checked all of the fuses and they look good. I spun them a bit in case there was some corrosion. I also took out each relay one a at a time to re-seat them in case of corrosion.

1 Reply

DR LOOT

MECHANIC
2,311 POSTS

First of all 12V is not enough capacity in your battery it should be showing at least over 13v have you tried giving it a jumpstart? And make sure you have a real set cables, or you will be wasting your time, if it starts up you have a bad battery, if it does not, you may have a bad starter, you can have someone in the car with the key on start, and hit the starter with a hammer, if it starts, you have bad starter.