MDG400BWW Not heating

[twmattox]

Had the gas dryer for about 10-years now.  Had a decent number of issues...but nothing overly difficult to deal with.  However, for some reason, now it won't heat.  I originally thought the ignitor may have burnt out.  But, would like to trouble shoot this instead of just throw parts at it.  

From my understanding, there are 3 main parts:

Ignitor
Coils
Radiant Sensor

How do I figure out which of these parts to replace?  And are there any instructions anywhere??

Thanks

Model MDG4000BWW

[JWWebster]

Check the flame sensor for continuity, the ignitor for continuity. If both work but  heat is intermittant the coils need replacing. if nothing is working check the fuse and control for continuity

Click on pic to enlarge