Troubleshooting dometic propane furnace

Hi all, 

I'm looking for any advice on next steps trying to troubleshoot the propane furnace in my Lance TT. I believe it's a dometic 19k BTU model number: 32825

It cut out the other day, with no prior issues at all, and been running all winter. I've tried troubleshooting a few things, and have ended with it cycling three times for a few seconds, blower coming on, sounded like it was ignited (and one time, it pushed warm air for a few minutes before cycling off), I can hear the clicks during the ignition phase, and then it shuts off, and I get ignition failure lockout code. I disconnected the gas and put eyes on the ignition components, and there was a steady spark between them it seemed. 

I removed the sail switch and cleaned some dust off it. There's a little bit of dust inside the blower that I can't figure out how to easily get to or blow out. I removed the burner, and didn't see anything obvious, though maybe the porcelain piece is cracked? Photo below. Gas is good, stove and heater work fine. Blew compressed air through the gas orifices and didn't notice anything. 

Any ideas on the right parts to try or other steps? Thank you so much!