Product review (5 stars): This probably not why your pizza isn't nicely cooked.
Let me guess.  You've just stuck a pizza in the oven & set it on convection bake & the convection fan isn't turning even tho the control panel shows it turning.  GE Profile Convection Range JGB916WEK3WW is 12 years old, so you figure the convection fan has put in it's time & bit the bullet.  Probably wrong.  You replace the fan & the new one doesn't turn either, so you replace the control board, WB27K10178&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/GE-WB27K10178-Control-Glass-Touch/dp/B002M65QO0/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">GE WB27K10178 Control Glass Touch</a>&nbsp;It's pricey, but that's the next logical step & we gotta have nicely cooked pizza.  Also probably wrong.  The last thing is the oven door switch, WB24K10020.  It's actually two switches in one; one turns the oven light on when the door is opened & the other one lets the convection fan turn when the door is closed.  That second part has probably failed...  Amazon does not even have a listing for the switch & most of the appliance places are out of stock.  Must be a lot of them failing at the 12 year point.  Good luck with your search.

This is a nice fan, it's easy to install, & it lasts a long time if that's any consolation.  The control board is also easy to install, however the switch requires virtually taking the range apart...