Vent fan not working on high or low.

Hello Gerardo,

This sounds like your main control board may be bad.
I seriously doubt this part is still available, however you can check here:
Goldstar Microwave Exhaust Fan Not Working

Fan works when component heat is higher so its normal.

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"

Some interesting reading on page 8 of the owner's manual:

"Boilovers cause smoking and greasy spillovers that may ignite and spread if the vent fan is operating.To minimize automatic fan operation, use adequate sized cookware and use high heat on surface units only when necessary."

And on page 20:

"If the temperature becomes too hot around the microwave oven, the fan in the vent hood will automatically turn on at the LEVEL 2 setting to cool the oven. The fan will automatically turn off when the oven has cooled down sufficiently. This is an automated process and cannot be turned off. The fan may stay on for 30 minutes or more after the cooktop and microwave controls are turned off. The Vent Fan will only operate in 1~4 levels modes while the microwave is working."

"Using the Vent delay off button
1. Press the Delay Off button once to turn the fan off after 1 minute.
2. Press the Delay Off button twice to turn the fan off after 3 minutes.
3. Press the Delay Off button three times to turn the fan off after 5 minutes.
4. Press the Delay Off button fiour times to turn the fan off after 10 minutes.
5. Press the Delay Off button five times to turn the fan off after 30 minutes."

If for some reason you don't have your owner's manual, you can still download it free here.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer

There are typically 2 fans in these units. The fan that cools the magnetron and then the vent fan that intakes from the top of your stove then vents the air out or away from the unit. Are the lights that shine on the top of the stove working?? Sometimes if a bulb blows violently it can blow a trace off of the back of the main circuit board and that trace may also supply power to the fan

A low tech solution worked for me.

I too was getting the "Vent Fan Off" message, and despite the fact that everything else worked fine with the microwave, I turned the breaker off and back on from my electrical panel. The fan works fine now.

the fan has to stay on,thats the way they are made

is the turntable working

check the control unit and high voltage circuit, and megnetron, high voltage diodes, wiring and high voltage fuse etc.,

From looking at the owner's manual, it looks like the vent fan is only supposed to come on when the internal temperature of the microwave gets too high OR when you press the VENT FAN pad. Here are a couple of fan-related excerpts from the owner's manual, which can be found here: http://products.geappliances.com/ProdContent/Dispatcher?REQUEST=SKUOBJECTS&DOCUMENT=Use%20and%20Care%20Manual&SKU=JVM1840BD (or the better URL here: http://tinyurl.com/yn7r6g) Automatic Fan An automatic fan feature protects the microwave from too much heat rising from the cooktop below it. It automatically turns on if it senses too much heat. If you have turned the fan on, you may find that you cannot turn it off. The fan will automatically turn off when the internal parts are cool. It may stay on for 30 minutes or more after the cooktop and microwave controls are turned off. - Vent Fan The vent fan removes steam and other vapors from surface cooking. Press VENT FAN once for high fan speed, twice for medium fan speed, a third time for low faw speed, or a fourth time to turn the fan off. Press the VENT FAN BOOST pad for extra fan speed. - Hope this helps.