I have a GMP 125-5 Changed hi limit and board. Soon as it is powered up the blower comes on even with the T-stat in the Off position

You have more than one limit switch did you check them all? Did you check for polarity correct line voltage on the control board? Last but not least did you check the low voltage fuse on the control board to make sure it wasn't blown?

You still have an open limit. Could be an auxiliary limit... Check for continuity on all of them.

Hi
I have a goodman circuit board GMP 125-5 and recently does not have heat.
The "ignitor" glows red.. but not spark on the sensor (bought a new one ) and the circuit board has 1 red LED that is on. Any suggestions will be helpful.
Thanks in advanced
And by the way.. A/C works fine