I have a carrier 58pav furnace, and it won't light.
Here is the sequence that I notice.
1st the furnace turn on and the fire kick on for 5 sec and then shut off
This happen for a second and third time.

I spoke to a HVAC friend (he is in another state) and he said sounds like you flame sensor. I replace the flame sensor (carrier OEM part) however, nothing change.

Then he said that the Ignitor maybe bad and I replace that also no luck.

Now I notice when I turn on the main switch the blower motor runs constantly, thing else happen, the blower motor does not stop running.

There should be an error code on the control board. Inducer fan runs all the time when trying to start?