Truck Repair: cummins m11, cummins m11, screw job

Question
Having electircal problems with a 1994 M11 in a Freightliner tractor.  I know that I have a bad wire to the fuel solenoid from the ecm, but is there a procedure for troubleshooting the ecm itself?  Engine truns ofer but will not fire, fuel solenoid is operational and energized with a junper wire.  Local Cummins shop wants to replace ECM and wiring harness ($4-6000,  $7500 truck.)  How detailed are the Cummins repair and troubleshooting manuals?  
Thanks for your time.
Kevin K

Answer
$4 to 6K sounds like someone wants to give a screw job.If it is a Celect Plus,the engine harness is both sensor & actuator harness,it is around $600. The books are pricey,like $100 but there is 2 manuals for electronics.They will tell you how to check it completely.