I have a Trane model TUD090A948A0,
Thermostat will call for heat by closing contact, then the vent motor or inducer draft motor run , then pressure switch contact close, give power to ignitor control module, and ignitor light up, but the problem I have here is, sometime the ignitor stay ON, with no power to activate gas valve solenoid. When the ignitor stay on problem, I had to reset by turning thermostat to OFF.