Yes the ohmmeter goes to infinity when closed.
Another thing is limit switches sometimes have resets which is a small button on the switch you and go through the unit and look for and reset these if you have them, I would also go through and check all the wiring connections I often find a loose connection to be the cause. Have you tried eliminating the thermostat and its wiring from the equation, you can do this by finding the t.stat connection at the furnace and connecting the r and w terminals with a small piece of wire when you do this the furnace should try to start.

These are things that I do first when trouble shooting a furnace, but based on your first couple of posts on this subject make sure you check the pressure switch on the exhaust. It should close as the draft inducer motor starts. The purpose of this switch is to not allow the burner to light until the operation of the draft inducer is verified by the switch.