How to stop a DDEC engine from the rear start panel?

[Iceni John]

I'm trying to replace the three switches in my rear start panel that the previous owner took out (don't ask me why!), and I've got the Safety and Start switches working as intended.   However, I just can't figure out how best to shut off the engine from the rear start panel.   I have the original schematics, but I think their draftsman was dyslexic or smoking something when he drew them because they simply won't shut off the engine if I connect the Stop switch the intended way.   Interrupting the power from the front start solenoid to the rear solenoids won't stop the engine either!

Because there's a 12V constant feed from the batteries to the DDEC Power relay in the front junction box (wire 99 from the 5A fuse), I disconnected it when the engine was running, the engine stopped (because the DDEC was no longer live), and when I reconnected 99 the DDEC came alive again and I could restart the engine from the back.   That's exactly the results I want, but I'm worried that I could harm the DDEC by shutting power to it this way.   Some years ago I rewired my battery isolator switch to eliminate the DDEC's constant slight drain, but then I had weird things happening because the DDEC was completely off when the bus was parked  -  the CEL and SEL lights would come on at random when driving, sometimes the engine would stop by itself with the SEL on after running a minute, and sometime the engine would mysteriously lose power for a short while.   When I restored the constant-feed power to the DDEC all those DDEC woes went away.   Evidently DDEC doesn't like having its power interrupted!   This is why I'm concerned about stopping the engine from the rear by cutting power to DDEC relay 4, even though it would only be briefly cut unlike before, and only on wire 99.   If I could ground wire 439 (DDEC ignition), that may also work to stop the engine, but I can't find it at the rear panel even though the DDEC schematic shows 439 and 99 branching off the main harness and going there "for test run only" (whatever that means!).

On a typical DDEC II bus how is the Stop switch in the rear panel configured?   Am I overlooking something obvious and better, or should I not mess with the DDEC at all?   Generally Crown's wiring makes sense to me, but in this case I think their schematic is whacko!

Any ideas gratefully appreciated.
Thanks, John    

[bevans6]

Why not just wire the rear "run" switch in series with the front "run" switch?  That would mean that you would need to have both switches in the run position for the bus to run, and if either one was in off, the bus would not run.  That is how my non-DDEC bus is wired.

Brian

[blue_goose]

Don't ground the ignition wire it is hot wire.  Take voltage off to stop engine.  The way it is wired the engine won't run unless the ignition is on in the coach.  The rear switch changes the start wire from the coach to rear and also kills it so it won't start from eather one.
Jack

[Iceni John]

Why not just wire the rear "run" switch in series with the front "run" switch?  That would mean that you would need to have both switches in the run position for the bus to run, and if either one was in off, the bus would not run.  That is how my non-DDEC bus is wired.

Brian

As always, the simple suggestions like yours are the best.   I'll just extend the front start solenoid's ground wire to the rear start panel and ground it back there at the Stop switch.   Simple!   This way I'm not dinking around with the DDEC or cutting the DDEC's constant-on 12V feed from the batteries.   I'll buy 50 feet of 14 AWG black wire  -  I've run so many extra air lines and wires along the frame rails that this will be easy(ish).

As usual, I was over-thinking this.   I was distracted by the original wiring schematic which is wrong in this case!   KISS is good.

Thanks, John