The oven heating element seems to be working but the fan is not working. It appears that the oven is reaching temp very quick and there is a red glow coming from the back of the oven which is where I assume the heating element is position? The grill is working fine.

Your wiring diagram and parts schematics are here in the link below. Normally the bottom element does glow read hot after a couple of minutes. Broil elements last a lot longer because they aren't used as much. There is only one Control Board. If I was guessing, I would say the temperature sensor is at fault. Elements either work, or they don't, but you can easily test continuity with a meter. Many parts are discontinued.

https://www.searspartsdirect.com/model/3f7nkrfnvp-001428/frigidaire-pleb30t8ccb-electric-wall-oven-parts

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oven display element supply all working perfectly
only 1 problem i face oven did not heat up...
plz help me quickly
thank you
Regarded
Hannan Ashraf

Thanks for choosing FixYa and welcome. you have a electric oven or a gas oven that won't heat or doesn't heat properly, here are some things you will need to check. The most likely cause of a oven not heating correctly is a defective heating element. You have two types of heating elements in your oven. The bottom element(s) are the baking elements. The element(s) on the top are the broil elements. If you don't see the bright red glow from the element, chances are they are not working or not working correctly. If a heating element is bad, you need to replace the entire element. If your oven is warm and not correctly hot, one of the elements may be bad. In most ovens, when you preheat, both elements are used. This would make the oven to appear like it is working correctly but it is not. If the elements are not working, they might not be getting power. Test the wires to the elements with a voltage meter to make sure they are getting power before you decide to change them out. Many electrical ovens have a sensor that monitors the oven temperture. Ovens that have this sensor usually contain a digital display on the oven. The sensor could be defective. Those without the sensor use the basic mechanical system to control the oven temperature. You also want to check the thermostat sensing bulb. Make sure the bulb is good and has not come loose. Now, if you have a gas range oven that doesn't heat properly, first, you want to check your bake igniter. It may have burned out or it could be not working properly. It will be located near your burner. It is also possible that you are not getting gas to the burner. If so, it may be the gas safety valve or the igniter. You need to check your selector switch and thermostat as well. They may be defective. Always make sure you test the parts for power with a voltage meter of some type before you decide to change the part. If you have a part that appears to not be working, it may not be getting power because of a bad wire or broken connection.

you may want to check to make sure both elements are working, if only one is working it will take longer to reach temp and to cook

You to check the element with a meter to ensure if you are getting a sapply to it, if you are, then the new element is faulty, if no supply, then probably ythe thermostat is faulty, also check for broken or bad conn ections.

I
make sure the fan is working o/k, because if it is not, then the element will get bright red hot.
If the fan is working o/k, then the element will still get red hot, but not bright red.
If the fan is not working, then it needs replacing.

The coils should glow red when working. If the lower (bake) element does not glow it may be burnt out. Some ovens cycle the bake and broil elements during preheat and that mey be why you are getting some heat.

it sounds like your gas valve isnt opening

the ignitor is moast likley bad, look for a hot spot on the ignitor showing a open on the filament.

Most modern gas ovens and many broilers use a "glow-bar" style of igniter that glows red-hot to ignite the gas. If the igniter doesn't reach the proper temperature, the gas valve won't open. You may need to replace the igniter.