Electrical burning smell

[rodder]

I replaced the flame sensor with success and no issues as covered in the topic "No Sustained Flame". The furnace have been idle for about two weeks, now we have 90*F temperatures. So last night I put the stat on auto/cool to cool the house. Cool air was coming out alright but with it a smell of a burnt circuit board, not a burnt wire. It's like when a TV goes south. I put the stat on Fan/off (just the fan) and the smell is not there. Fan runs ok but I don't know if it's in lo or hi speed. Was told it's the blower motor, but it blows. Any ideas?

[rodder]

Anyone have any idea before I call a service tech?

[4ftBanger]

If everything continues to run and the smell goes away when you shut it off, then it's likely the blower motor is overheating. The smell is probably either the winding insulation or the bearing grease beginning to burn. Typically the conductors on a circuit board (or transformer) are much smaller and everything will stop working when it starts to burn out and produce a smell.

[rodder]

4ftbanger - I appreciate your response. But I called in a technician and found the universal module was burnt. He said the cool air was just recirculating air because the a/c was not activated. He showed me burnt area and a new board fixed the problem. He also checked the motor and a/c system and all was fine. So thanks again for taking the time to reply.