If you are experiencing issues with your Grid+V3 and your fans are not spinning, up we recommend you check the specifications on those fans. The Grid+V3 supports up to five watts (5W) of power draw per channel. If a fan were to exceed this threshold then it will trigger the fail-safe the Grid has and shut off all fans.
If you do find that a fan you are using does exceed that limit then you would need to disconnect that fan from from the Grid+V3. To do so, first power down your system fully and turn off your PSU. Wait 10 seconds and then remove the fan, at this point you can turn on your system and the fans should spin up.
If they do not spin up, please contact our customer service team here for further assistance.