So my 2003 discovery with 110,000 miles on it decided that it was going to play silly this morning. It wil start and run fine, no problems, the break lights come on when the pedal is pressed but it's locked in park. Can remove then centre cover over the shifter and press the button to move it, I can use the T4 hand scanner to FORCE move the shifter out of park. I can 12v jump the switch to move it out of park BUT when trying to move it normally its locked in park????
Out of park it will shift normally. There are NO codes for the transmition. There are NO lights flashing on the dash but the thing will not move out of park without doing any of the above. ALL fuses and relys are good and the break switch is good as, hence the break lights coming on. It was not a problem yesterday and shifted out of park normally, this morning... no!
So throwing this out there to see if any one else can think of where I should be looking. Thanks in advance

 

Sound like you covered all the electrical stuff. Maybe a mechanical failure in the botton on the gear shifter.

 

Time to take the shifter/release button apart...

 

I would venture to say it's still the brake switch. If I felt it correctly, there are THREE leads on the switch. This would lead me to believe one is Brakes and one is the Shifter. Since you can get the interlock Switch/Solenoid to operate electrically using your scanner, then it's not likely that switch, but rather the feed of electricity not getting to the switch.

Try heavily spraying the BRAKE switch with WD-40 and then operating it back and forth a number of times. Sometimes, it gets gummed up in there and just needs to be worked clean. Be sure to lay a large towel below it before spraying so as to save your carpet.