I know nothing of the testing you have done but that may not be the next logical step depending on exactly what happens when you turn the key on. Turning the key turns a pin running under the steering column (that pin is a not uncommon DCJ failure point as it can crack causing intermittent start or break causing no start) which then turns on the ignition switch on the left side of steering column (another not uncommon failure point which produces no start but may, I'm not sure, turn radio and other stuff on) the ignition switch then tells the ECU it's ok to engage the starter and start the engine.
Check out this link (
viewtopic.php?f=5&t=61233&p=678574&hilit=+brother#p678574) as both parts are relatively cheap and easy to replace. If you need a writeup email me.
As to the shift interlock cable geordi says "Pull the shield off the top of the gear shifter, there are 2 small cables in there; the passenger-side one is the sensor cable, it's not electrical, it's an aircraft wire; the sensor is actually located under the steering wheel. Unhooked, problem solved permanently. I thought of a quick way to test the actuator cable without pulling anything apart on the shifter console - With the engine off and in park, pull back slightly on the shifter to apply tension, and try cranking the engine. If it doesn't go... The cable is the culprit b/c the tolerance (and how much it moves normally) isn't much. The cable is pushed toward the front of the vehicle when the selector is in park, and just shifts backwards slightly when the selector is anywhere else. All you need to do is unclip the end of the cable, and push the end into the sheath until it stops (about 1/4") and tuck it away in there. This won't affect anything else in the operation of your CRD, the shift interlock (that foot-on-brake-to-shift) idiot switch will still be there and functioning... Unless that 2-wire connector happens to "fall out" like it did on mine. Strange how that happens sometimes."
As just mentioned battery can be an issue to even if it "seems" good a relatively insignificant lower voltage can annoy the electronics and produce a no start.