Trane unit cooling only w/ econ.
I cannot get 1st stage cooling to fire in test mode and only C2 comes on when the unit goes into cooling. I unplugged J4 on RTRM to eliminate all optional boards, but it still won't fire off in test mode. It doesn't have the LON card. I have verified 24 volts on the LPC return at the board and I can put 24vac to the out put on the board and it will fire, but not at any other time.
The question is am I missing anything? I am leaning to a new circuit board, but since I don't work on these things everyday I thought you guys might have some advice.