Noise on high speed

See if you blower speed is set to low speed in the heat mode.
I think what might be happening is the blower is set to low speed in heat and when you switch to automatic, the blower is switched to high speed. You may have to change the blower speed to high in the heat mode. If not you may have an airflow problem such as a Dirty filter, ducts not sized right, dampers on the room outlets closed.

Sounds like high blower relay is bad

still nothing,????
why do this backwards. ??
or not using simple diagnosis>?
so really you failed to state the beginning symptoms?
was it just just noise. or noise and no blow.
or the noise is gone,, but my fix broke the blower.
there will no heat not moving, if the blower is dead.
get heat , moving in non circ, mode.?
sure i bet you do an that is SOMETHING.
does the blower make sounds like a normal blower, then if no air flow
the dampers are bad.

blower silent? on all speeds, , do say so.
blower works only on high (sounds) ?
if the blower is running, surely you can hear it spin fast.
and there is no flow, the damper is bad or the blower fan blade set screw
is missing and or loose. did you check that screw first. before.
replacing the motor? id not ever skip that step.
we can not help you ,with no facts or symptoms but still nothing.

I would unplug the oven for 2 minutes to do a hard reset and try it again, just in cause there was a glitch.

Without knowing your full model number from the tag on the oven, I would wonder if it has a separate internal cooling fan from the hood vent exhaust fan. It could be an unrelated issue.

For more free DIY and other help & advice, feel free to contact me with your full model number and FCC ID number from the tag on your oven.

William E. Miller, AS-EET
[email protected]
http://www.microwavecontrol.com
Microwave Oven Control Panel Repair Nationwide
"Recycling by repairing since 1982"

For the screeching noise you need to replace the blower motor and for the blower motor speed you need to replace the blower motor resistor.

Either its developed the same fault or the fan motor bearing has failed, needs greasing or, if there's a belt, the belt is slipping.

The indoor blower motor is sometimes a 3 speed motor.The heat usually works on low or medium speed.But the a/c is usually on high speed,this gives greater air flow across the evaporator coil to give you better cooling,also better air flow at ducts.These speeds are usually wired through a relay in the inside unit (air handler).They can be changed.If you go to thermostat and put the fan switch to "on" the blower should operate on "high" speed.With the fan switch set to "auto"the operation will determine the fan speed.Hope this helps. Gregg

usuall a schreeching noise during blower opperation is bad berrings which would need to be replaced. Most unit warrentys for newer units cover five year parts and sometimes 10 for heat exchanger. But most do not cover labor. Or the blower may just be off balance and metals are rubbing. eaither way your proubly gonna need a tech. good luck

You can Check those with a Voltometer But, Ultimately you will have to Change the Blower Motor.