I have a 2005 6.0L powerstroke turbo diesel.. its stuck in a low gear an the switch will not crank it you have to jump the starter. Any suggestions?

. Remove and fully charge (or replace) both batteries. Clean the battery terminals and cable connections, including those going to the starter motor.

. Check all under hood and under dash fuses with a test light or multimeter.

. Check the ignition switch for wear, pitting, or melting. Examine/clean the wire and connection going to the starter solenoid.

Your diesel is stuck in low gear?? If this is the case then your truck won't start by key because the transmission has to be in park or neutral for the starter to get the signal. Multiple reasons try truck would be stuck in low gear, the low reverse sprag clutch is common in them but may not be the issue, tranny shop.