Trane XR80 blows cold air.
Inducer motor comes on, glow bar glows for few seconds than goes out and inducer motor shuts off. Immidiatly after the main blower comes on and blows cold air. Will blow until main switch is turned off. Error code is 9 blinks. Replaced the glow bar and same problem.

Strange part is sometimes the furnace works fine. Usually acts up at bed time.

Please help