I've said this previously...
When calling for heat, the furnace is designed to come on, run the fan a few moments and prove out it is running via a sail switch. This is necessary because they use part of the fan for the combustion chamber. (in a separate part of the furnace)
If the control board/module doesn't see voltage (through the sail switch) it won't try to light the furnace because it deems it unsafe to light.
If the sail switch circuitry is working OK, the furnace will try to light three times.
Then, if it fails to light, the control board/module goes into lock-out and it is necessary to shut the furnace off to retry.
If the sail switch is stuck, the furnace will run a few moments (but not try to light) and then shut down.
Alternately, if the control board has problems, it can cause similar conditions.
You really need to follow the troubleshooting procedures in the service manual and determine what the culprit is.
is a Suburban service manual. Pay attention beginning on page 23.