Symptoms
- Microwave function works but convection/bake mode doesn't heat
- Convection works but microwave mode doesn't
- Fan for convection may not run
- Rack included for convection use only, not standard microwave mode
Likely causes
- CommonConvection heating element failureThis separate heating element can fail independently of the magnetron.
- CommonUser confusion about which mode is activeCombination units often require selecting a specific mode, and it's easy to leave it on the wrong one.
- PossibleConvection fan motor issueA failed fan can prevent even heat distribution in convection mode.
- PossibleControl board fault affecting one function but not the otherThese boards manage both systems and can develop a fault isolated to one side.
What to do
- Confirm which mode you intended to use and that you selected it correctly according to your manual, since combination units often have several distinct modes.
- Test the microwave-only function with a cup of water as described in the not-heating guide.
- Test convection/bake mode separately with the oven-safe rack in place, if applicable, and check whether the interior heats up like a small oven.
- Listen for a fan running during convection mode, since these units typically circulate hot air.
- Never place the metal rack in the unit during standard microwave-only mode unless your manual explicitly says it's safe to do so.
- If one function works and the other doesn't after confirming correct mode selection, have a technician check the specific failed component.
Tools and parts
Convection heating elementSearch: “microwave convection heating element replacement”
When to call a pro
If one function (microwave or convection) fails while the other works, have a technician diagnose and replace the specific failed component.
Safety
Use caution
Only use the metal rack in the mode your manual specifies as safe; using metal in standard microwave-only mode can cause sparking.