One XLO Simmer Burner failed to operate. Exchanging the potentiometers moved the problem to the other XLO burner indicating a bad potentiometer. Opening the failed potentiometer revealed an open in the switch circuit trace. I installed the new Bosch/Thermador kit with the new potentiometers and simmer control module. Now neither XLO burner will work - no indicator light, no solenoid valve operation, no ignition spark, etc. The ignition control module works fine when operating the two other standard burners. It creates spark at all four burners just fine. The wiring has been checked as during the exchnage of modules I only moved one connector at a time to the new module. Both solenoid valves have been checked with a VOM and indicate the proper resistance.

What should I suspect and/or check next?