I have a Trane XE70 furnace. I recently replaced the ignitor (it was abviously bad) and I now cannot get it to run at all.
The ignitor glows, then the system cycles it off then on 3 times.
The red LED then blinks constantly, no code just a constant flash.
The gas valve is apparently not sending gas.
What can I do to determine the problem? I can use electrical test equipment ( I have a Fluke vom).
Thanks

Check the label on the module for a legend. In most cases a constant rapid flash indicates a polarity problem or a control diagnosed self-fault (replace control). Check for 24 volts at gas control during ignition trial period.

Thanks, KC. There is no legend or I would have known that already.
I have no voltage at the gas valve so I suspect the control unit may be at fault.
I'll check the wiring and connections first tomorrow AM.
Fortunately, I have a good standby heat source.

Check for 24 volts at module gas control terminals during ignition trials. If output is measured at module but not at gas control, look for an open limit switch or fusible link.

Thanks again KC.
There was only 7.2 volts at the gas valve during cycling.
To confirm the control was the problem, I jumped 24 volts from the thermostat connection (during the ignition cycle) and the gas valve opened, ignited and warmed the house just fine. Of course, I didn't leave it jumped this way.
I found a control box this morning and installed it.
The system works perfectly.
Thanks a bunch!
Jon