The key turns but won’t turn over

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Glasfryn

Glasfryn

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OK so try the first bit, running the gear selector up and down while holding it in start. If you don't get engine turn over then you need to test you have power arriving at the starter solenoid on a violet or violet/white wire. If you have power there then that just leaves an earth bond strap broken or a break in the main live feed from the battery to the motor (unlikely) or ultimately the starter unit itself. Money is on the inhibitor switch or wiring from it.
With foot hard on the break pedal and handbrake on then I’ve held the key in start while Running the gear selector up and down - there’s no response 😒
 

Pontoneer

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I still think it is most likely the starter motor or the solenoid ( the small cylindrical object on top of the starter ) .

Give both a good whack with a hammer and try it again .
 

Pontoneer

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One further thought .

The W123 uses the old bullet shaped fuses which are prone to corrode at both ends and stop working.

While the starter itself draws far too much current for a fuse and is connected directly to the battery , the circuit actuating it will be on a fuse .

Take a look in the fuse box ; you may just have a blown fuse , but even if you don’t , inspect the ends of the fuses where they connect to the terminals - quite often these fuses will either corrode or burn away where they contact . You need to take each individual fuse out and inspect both ends .

The chart in the lid of the fuse box will tell you which fuse protects the starter circuit .

If the fuses appear in poor condition, I would replace all of them . Just pay attention to the colour coding so you are putting the correct values back in . I used to routinely replace all the fuses when I ran these cars as corroded fuses were the cause of numerous problems ; it is both cheap and easy to do .

You can still get these fuses in any branch of Halfords , some petrol stations still have them , but some don’t .
 
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Glasfryn

Glasfryn

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W123 does anyone know if there is a sensor on the automatic gearbox that recognises it is in park?

or will the car start in neutral
 

Halla

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Hi,
I had this problem twice on my e280, w reg. there is a two wired plug in the engine bay fuse box. This runs a small fan for the ecu. I pull this out and check a 10 amp fuse, f3 which has blown.
Car starts,or turns over again.

At the same time the gearbox will be stuck in park. Check your fuses.
 
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carat 3.6

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W123 does anyone know if there is a sensor on the automatic gearbox that recognises it is in park?

or will the car start in neutral
It will start in park or neutral, as the others have said my moneys on the starter motor.
 

Gbrowncls55

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starter motor relay or solenoid.
 
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Glasfryn

Glasfryn

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Thanks to everyone who has replie, I have had an auto electrician to solve the issue and it turned out to be the gearbox linkage arm, it was locked in reverse therefore it disabled the switch, he popped the linkage arm back in and the gearstick selected the gears and hey presto, it starts and drives - weyhay!

now back to the original problem of cutting out when the engine is hot
 

Pontoneer

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W123 does anyone know if there is a sensor on the automatic gearbox that recognises it is in park?

or will the car start in neutral
Yes , there is an inhibitor switch on the side of the gearbox
 

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