If you take the front of the cabinet off, and leave the door switch connected. turn on the dryer. you should see a bright glow coming from the bottom inside off the dryer. if igniter does not glow then your problem could be your igniter or a thermostat. if ignter does glow then the thermostat is ok and the problem could be the igniter is not strong enough or the gas colud be off. if gas is on and igniter glows the problem is your igniter.
There should be a gas igniter, inside of the burner chamber, that will glow bright red before the gas will be allowed to flow. If the dryer model that you have has a flap on the front you will be able to observe this otherwise you will have to remove the front of your machine to check it. If you post back with your machine model number I will be able to assist you further.
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