The cooling test sequence for this board, says to jumper Y & G to R. Make sure the fan comes on, and spins up to the proper speed. Then remove the jumpers, and check the fan off delay.
If the blower does not come on, verify that the COOL terminal is energized. Use a voltmeter between COOL and neutral, and verify 120 volts (with jumpers in place).
If the COOL terminal is energized, check the motor and verify all speeds are working properly.
If the COOL terminal is not energized, the board my be bad.
According to the schematic you've provided, you have a multispeed blower (which is quite common). The speed at which the motor runs, is determined by which wire is energized. Energizing the red wire; for example, will run the motor at low speed. Energizing the black wire, runs the motor at high speed.
Before you disconnected the board, one of the motor wires was connected to the HEAT terminal on the board, and one was connected to the COOL terminal. Looking at the ladder diagram, it looks like the blue (MED) wire was connected to the HEAT terminal, and the black (HI) wire is connected to the COOL terminal.
If you've run the tests described above, and found that the COOL terminal is energized when the jumpers are in place. You can try connecting a different speed wire to the COOL terminal. If the motor spins up with the other wire connected, it means that the original speed is dead or something's wrong between the board and the motor.
It looks like the LO speed red wire is attached to the M1 terminal on the board. I'd swap that to the COOL terminal (just temporarily for the test), and see if the motor spins up when the jumpers are in place.
WARNING: DO NOT run the A/C for long with the motor at a lower speed..
Best Answer
If the evaporator will ice up depends on the type of control if it is orifice or capillary tube control it may Ice up but if a thermal expansion valve called TXV this regulates the flow and it should not but I have seen TXV controlled system ice up a few times. As far as your system not shutting off when the temp is reached this is to keep the system from short cycling there is a setting sometimes called “dead band” usually around 3 degrees and is set in your thermostat it may be a setting like +2 -2 this would be a 4 degree dead band or the thermostat won’t turn the heat on until 2 degrees below set point and won’t shut off until 2 over set point same with the ac, you can usually change these I change mine based on season +0 -2 is my summer setting and +2 -0 is my winter setting. If it takes 10 minutes to change 1 degree a 2 degree dead band is ok but if you reduce it two far your energy cost will go up and the life of your system may be reduced from the repeated startups.