Ignition staying running if key removed and lights are on?…⚡️🤔🙄

TheCornishman · Jun 30, 2024

Evening all

So yesterday my 300tdi mastered a new party trick…

Starts fine, runs fine & stops fine…when the lifts are off but if my lights are on it continues to run even after the key has been removed from the ignition

….naturally I’m concerned this could produce further buggeration or even

if I don’t rectify it.

I saw a mention that another thread touched on this but haven’t been able to find it.

My gut says ignition switch fault but can anyone share their experience of this please?

Thanks G

backinblack · Jun 30, 2024

I have the same issue on my L322 MY2005 but only on main beam. I mentioned it a few weeks ago so it may be that post that you saw.

boguing · Jun 30, 2024

Try everything else and look for odd behaviour, indicators, hazards, brake lights - making them all operate with lights on, horn etc with someone outside looking for dim things or stuff coming on when you haven't commanded.

There are various earth points and your problem could be either:-

One of the earths is shared by the lights and something going to the immobiliser ecu, or to the fuel shut off solenoid. A nuisance. Other odd behaviour would support that theory.

Chafing in the wiring loom anywhere from the ignition and column switches onwards. That's where the fire risk comes in, but possibly only when it's got power.

Graculus · Jun 30, 2024

I'm tempted to say side light filament touching brake light filament but with such a basic setup, the brake pedal switch *should* prevent that.

mystery · Jul 1, 2024

is it fitted with a trailer socket has the screen leaked recently (headers) ,dim dip relay ,column switch checked etc etc more info please

miktdish · Jul 1, 2024

It's running because there is a voltage on the cut-out solenoid (STC3254).

Using a volt meter.
With the engine and light off - check the voltage at the solenoid (use the engine as ground).
Ignition on - check (should be 12V)
Sidelights on - check (still should be 12V)
Headlights on - 12V
Turn off the ignition and remove key - should be 0V (engine should stop).

If there is still 12V then turn lights to sidelight only.
If there is still 12V turn off side lights.

Start the engine and repeat ....

Check the earths on the bulkhead and the earth under the car near the gearbox, there should be a connection from the gearbox to the chassis and from there to Negative on the battery.

Let us know how you get on.

chrisstdt · Jul 5, 2024

I've had a stop solenoid go bad so you would have to stall it to stop the engine

Could it just be a coincidence thar she's playing up when the lights are on ?

RustyDefender · Jul 5, 2024

plugs from the bulkhead in the right plugs?!

Ignition staying running if key removed and lights are on?…⚡️🤔🙄

TheCornishman

Active Member

backinblack

Well-Known Member

boguing

Well-Known Member

Graculus

Well-Known Member

mystery

Well-Known Member

miktdish

Guns n Chainsaws

chrisstdt

Well-Known Member

RustyDefender

Well-Known Member

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