Mercedes S500 w140
1994

i came across a starting issue one night at the petrol station, filled up with gasoline, upon starting it sounded slugish (like a flat battery) but started after 2 cranks. Drove to the shop and it failed to start.

All the lights are on, radio, air con, etc. I turn the key and hear One Click.
Tried many times, same. Called the breakdown service, after waiting 30 mins i tried again, and it started. Drove home.

Next morning it started and i went to get the battery charged.

it ran for a week without issue. (it has been a good starter in the past, first or second crank without the accelerator)

Then it happened again, just a Click, this time i had to leave it overnight. Next morning it started, and i drove home where it has sat ever since...

Thinking it was the battery, i took it off and went to charge again, came back and still the same, all the lights, just a click.

So just to rule out the battery i got my friend to jump start me, the lights very bright, but just a click... Not the Battery.

Tried shifting in and out of Neutral, still the same.

Took of the Neutral to the battery and cleaned it.

Played with the key and batteries, doors open and lock fine. changed the Key Batteries, just in case.

Checked all the fuses, front and back, especially the Ciggy lighter (works ok)

I believe the next step is the Starter Relay ? How would i know if it is broken or Damaged ? Where is it? i am not a mechanic!

i appreciate any help, i wish to pin point the issue before i get the garage involved $$$$$ (i live in Thailand and a white face in a S500 and the garage owner thinks he has won the lottery, the merc dealer is 50m away)

Yours
Jon

I think i may have found the problem...???

But what is it?





It is a RHD car.
12 inches across from the fuse box and 8 inches below the Brake Fluid Res.

It is a very corrosive wire (approx 1 cm in diameter) hanging on by a thread or two.

If this is part of the ignition system, is it a specialized part? or could a local garage (Bosch) repair it or replace it?

Could this be patched to test if it is the problem? just enough to get me to the garage?

i appreciate any help

If you don't charge your cell phone, what happens eventually? Would you replace the cell phone battery because it was not charged?

Same with a car - the "alternator" charges the battery! Sounds like that is not working.

You should get about 14 volts with a voltmeter with the engine running when measuring DC volts on the battery. If 12 volts or less, then something wrong with your charging system - most likely alternator needs to be replaced.

Well YES, replace the wire. Don't you ever look under the hood? Also it sounds like you need to get a new 6 year battery of the right size and install a new regulator on the alternator. You may not need a new alternator. You don't say how many miles are on your car. Alternators usually give up at about 130K miles (250kms)
Anziani
'97 CL500 156K
'97 CL600 47K

1) Can you put up pictures from a greater range? Provide a more panoramic view? The detail in the posted pics is great, but hard to visualize the location in the car. Where is the battery located? Pic?

2) Based on your highlighted statement about a jump battery, there is a good chance of either the battery positive (+) lead to the starter motor being corroded through, or, the starter solenoid has failed.