John1

My blower on my furnace (Trane XE90) won't come on when the A/C (Trane XL1200) is on. If I turn the A/C off and put the fan to manual, the fan comes on with no problem. The condencer on the A/C unit will run, but not the inside fan on the furnace. Do I need to replace the board? Need help

kok328

Possibly a problem with the thermostat.
As far as I know, the thermostat will send a signal for fan through the same relay on the board when switched to fan "on" versus fan "auto".

paul52446m

Most of the electronic boards today, The green post is for manual fan runs the fan on a low speed like the heating speed. When you turn on cooling, the power comes back to the y post which goes to the condenser and also to a different relay that starts the blower on a faster speed. So i would say you have a bad board. Paul

John1

I went and bought a new one and replaced it, but that wasn't the answer. Same issues,
thanks for suggesting

John1

Paul, Thanks for the insight. How much of a problem is it to change the board? It is the UNIVERSAL HOT SURFACE IGNITION CONTROL MODULE (50A55-843) that needs to be replaced.

paul52446m

If you can let the board hang on the wires and then put the new board on furnace , then install one wire at a time. If you get those wires crossed you will have a real problem. Paul

paul52446m

Can you send me some pic. of your controls.
paulm989@hotmail.com Paul