Viking DSI Bake Ignitor Won't Spark

I have a 10 year old Viking gas stove/range, which use Direct Spark Ignition (DSI). The bake ignitor will not spark at all, however the Broiler ignitor will spark and light up just fine.

Things that I’ve done so far:

• Replaced the DSI spark module. This did not make the bake ignitor spark.
• Replaced the bake ignitor with two different replacements. No spark still. I thought the first ignitor was possibly cracked or defective, so I ordered a second one from a different vendor, but same issue.
• Checked continuity on wire between DSI module and the ignitor. THe wire beeps on my digital multimeter just fine, indicating continuity is good.
• Replaced the gas valve on the bake portion. Gas is coming out just fine out of the bake piping, but no spark on the ignitor.

I am wondering what else there is to check or replace? Could it be a thermostat issue? I have not replaced that, but I find that hard to accept as the cause because the broiler comes on just fine. Is there anything else I can check with my multimeter? How can I test that the replacement DSI spark module is not faulty?

Thanks!