My 83 300D turbo won't start by turning the key to the "start" position. The battery is good. It will start by using a remote starter switch connected to the contacts on the passenter fender. The only thing I feel it could be is the ignition switch. Are there other possible problems? Thanks in advance for the guidance.

try toggling the gear shift.
could be the nuetral switch in the transmission or the relay which cuts off the start circuit when once deenergised....to prevent the starter being operated with the engine turning