The B-C wire colors are in the 2nd of the 2 tests in the canned post below.
Also note the the spark should occur when the B-C jumper is removed, not when it is inserted.


==========canned post========>

Either test below can be done first, and both assume +12V at Coil terminal #15 with Key On.

(A) Hall Switch Test
1) Pull coil HT wire from distributor cap, attach/adapt to spare (grounded) sparkplug.
2) Remove distributor cap.
3) Rotate engine till an open Vane "window" is centered in front of the Hall Switch.
4) Turn Key ON.
5) Pass a feeler gauge blade (or similar) through the Hall Switch (simulating a moving Vane segment).
•) If the Hall Switch and ICU are OK, you should get a spark at the test plug and fuel pumps should run for a second.
•) Repeat step 5 as needed to verify spark and pumps.
•) If no spark, test ICU operation below (eliminating Hall Switch).

ICU Switching Test
1) Key OFF. (Coil wire and spare plug still set up as in Hall switch test).
2) Remove the 3-wire connector plug from distributor body.
3) Insert a jumper from plug socket B (Yellow wire) to socket C (Black wire). When jumper is REMOVED (step #4) the plug should spark, and the fuel pumps should run briefly.
4) Key ON. Check for spark and pumps as jumper is removed.
•) If Spark & Pumps operate briefly, suspect Hall Switch or wiring.
•) If no spark, suspect ICU or wiring.

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--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.