I have a Peugeot Boxer 1994 MWB 2.5 diesel, when I turn off the ignition the engine continues to run even if I remove one of the battery leads the engine still runs. The only way to stop the engine is to stall it. Also when the ignition is in the off position the oil light remains on but goes out as soon as I turn on the ignition, the two problems seem to be connected. Can anyone advise me.