Dryer blowing cold air

UNPLUG the dryer. This model you need to remove the two screws under the lint screen. Now use a flat blade screw drive and insert it in the gap between the top and the front panel and pry the top up. Now locate and remove the screws on the inside of the front panel in upper corners. The front should lift off. You will see the ignitor attached to the burner. You can try and replace the ignitor without removing the burner. Sometimes it is just as easy to remove the burner. Make sure the gas is shut off before removing the gas fitting on the gas valve. Be carefull and DO NOT touch the black part of the ignitor with your hand. It could ruin the ignitor with the oil on you hand.
If I can assist you further, please let me know.

Thanks
Vic