The cables have been replaced a month ago. This happens in sun, rain, hot and cold weather. I am running out of options. I might just replace the alternator and see what happens. The alternator in the car right now was a rebuilt. I changed it 4 years ago for the cost of $120.00 CND.

1-If you jumpstart it, do you leave the other car running?
2-Do you hear the starter relay if you try to start?

As soon as my 300E is started I turn the other car off.

Where is the starter relay located? I really have not paid any attention for any other sound. As soon as I find where the relay is I will Listen for it.

Thanks,

Fab

Y'know...for what you're spending throwing parts at it, you could have just taken it to a shop.

__________________
1989 300 SEL that mostly works, but needs TLC

Next time it's not starting try moving the shifter to neutral and see if it starts.
(could be an intermitant neutral saftey switch)

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

The starter relay (solenoid) is mounted on top of the starter motor. The big cable from the battery goes direct to this solenoid. If you start you should hear a loud click. If you jumpstart with a running engine the voltage is higher than normal. This may kick the soleniod into action.

I usually test is with a hand starter switch, two wires with clamps attached to a switch. you clamp them to the big cable and the + of the solenoid. Be carefull with this, the big cable is not protected with a fuse.

If the solenoid is working but not with the contact switch, the resistance of the contact switch or the neutral/park switch may be to high (burned or foul).

A DC amp meter makes this sort of diagnostics much easier. You can see where the electicity goes and how much.

And stop jumpstarting, if you have a really bad switch or wire you can start a fire! or ruin expensive electronics.

I tried everything that was suggested and the car still would not start so I decided to bring my car to a mechanic. The mechanic said it was the starter. I replaced the starter and the car starts everytime no problem. Thanks everyone for all your help. This site is incredable.

Thanks,

Fab