We did similar to get home 1 night. Wired up solenoid to the headlights. Headlights off - engine off. Wiring fault somewhere most likely the immobiliser on a 97 300tdi..Just put a 12v feed straight to stop solenoid and this will tell you if the fault lies there. You will need to disconnect to stop engine.
My 1996 300Tdi Defender has an immobiliser fitted as standard.Thanks
Don't have an immobiliser ECU its a 1996
I saw the ecu controlled one
We did similar to get home 1 night. Wired up solenoid to the headlights. Headlights off - engine off. ]
Never thought of that one before, will use it in future.