Possibly the keyswitch.
if the starter is not spinning and the truck motor is running
If the engine stops running when the key is released, then the ignition switch is probably bad. The switch will need to be replaced.
Have you tried changing the ignition switch?
replace the balist resister replace the balist resister
If it starts but doesn't stay running after you release the key from the start position, it means your ignition switch is bad. Not a huge expense.
Position 2 on a Mercedes-Benz ignition switch typically refers to the "On" position, where electrical systems are activated but the engine is not running. In this position, functions such as the dashboard displays, radio, and other electronic components can be accessed. It is often used for pre-start checks and enabling accessories before starting the vehicle.
Cycle the ignition switch on and off several times pausing briefly in the on position. This will prime the fuel system.
The function of a stop switch is to cut the ignition so the engine can stop. If the switch is in the off position and the engine isn't running, then to start the bike you'll have to put it to the on position.
Bad ignition switch?
The ACC (accessory) position on an ignition switch allows electrical accessories in the vehicle, such as the radio, power outlets, and dashboard lights, to operate without the engine running. This position is useful for using these features while parked, without draining the car's battery significantly. It serves as a convenient way to enjoy certain functionalities without fully engaging the ignition.
Turn on the A/C and then turn the ignition to the on position without starting the engine. The fan will be running if it is good.
Depends if you have the ignition running or just the say you left the lights on. If you just left the ignition on all night nothing will happen except just running out of fuel. If you left your lights on without ignition running your battery will die.