Air switch not closed due to low pressure differential. I found one other air stem located at the right top corner of the font inducer box. I swapped the 1/4" hose connection from the air switch to this 2nd stem instead of the original stem (at the left bottom corner) and blocked the unconnected one. My furnance starts immediately and works fine. My question is should the 1/4" hose be connected to the top right corner air stem in the first place ?