You don't want to run that at over 105 degrees. The cheap way is to drill a hole and use a food thermometer to determine the temp inside. Then start drilling more holes until the inside temp is within range. I assume this will make your dehydrator looking like a block of Swiss cheese.
Better way, build a regulator. I knew squat how to do this, and it took several trips to the hardware store to seperate the employees who thought they knew about wiring, from those who actually did. They advised me to use a fan speed regulator. Here is some pics:
BTW, for full disclosure, the above two pics are not mine. I too took advise on a hobby board on how to do this. If I knew who took the pics, I would give them credit.
Below are my photos of what was used:
If you do go to the hardware store, either bring someone who knows something about wiring, or find an employee who does.
Notice I drew a line on the switchbox so I know where to run it at 105º
I wish I had a pic of the unit as it stands now... it must have at least a dozen or more 3/8" holes drilled for venting besides the regulator to run it at that temp.
Hope this helps.