EMERGENCY: w123 no start
 

W123 300d no start

Put in park or neutral and not even a click from the starter. What the fudge is going on?!!! I came out earlier and it started just fine. Multiple times. Please advise

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Do you have the junction box on the inner fender in front o fthe battery? If so, jump terminals 1 and 3 after glowing the plugs. If you don't have that terminal box you will have to jump across the small terminal on the starter solenoid to the big main hot wire. Could be your NSS. There are instructions on here somewhere how to jump that above the drivers kick panel.

Have you tried bridging the starter terminals? There is a little plastic terminal box on the passenger side fender under the hood. Bridge one side to the other and see if it cranks.

I'll try that I left the car. I think I saw the thread on how to bypass the NSS.

I tried jumping it thinking the battery died but the radio and windows work. However I do not get a spark from it when i touch the jumper cables together ( not hold them. That would be dumb).

After I drop my gf home i get some sand paper and clean all terminals and bring some wire to bypass the NSS).

On my schematic for my w123.133
battery heavy cable goes to starter then to connector 105
red wire from c105 to the Main switch .
then to via a violet and white switch to the transmission switch
Then back to c105 on a violet wire. from there it goes to the starter solenoid

get your voltmeter or tester out.

Could be a dead battery. Did you leave the lights on? Battery could run the radio and windows but lack the power to engage the starter.

Is it at all possible that whatever device detects if the car is in Park is messing up? I've forgotten to put my car in park and tried to start it and it's just dead quiet, does nothing. Something else to think about?

Try what the other guys mentioned about jumping the terminals on the starter. Had my 300D do this a couple times and can't explain it, so now I keep a pair of needle nose pliers with me to jump terminals if needed.

Nothing was left on. I tried jumping it with no click from the starter. Usually when jumping a car with a low battery at least the starter clicks. And I tapped on the starter solenoid too

What gauge wire should I use? I have pliers but they are not insulates.

Be careful there jumping terminals. If you short out the battery you will likely melt any wire and hand that is holding it.

Use a 12v test lamp to see which ones are hot and which are grounded.

When I am troubleshooting I usually go to a mid point in the circuit and figure out which side of the fault you are on. Then I divide the distance again. Good luck to you.

I do have that terminal. Now which is 1 and 3 when looking across to the drivers side while standing on the passenger side fender?

could I not just use my volt meter to see if I get 12v's across the two points?


that would be the wonderful netural start safety switch. Which will work if you put the car in neutral to start when they go bad.

Try first and last.