replying to trader_4, Cynthia wrote: I have a Range Top Jenn Air (central section) Downdraft unit, that came with my house which was built in '87. The fan has always done the same, on/off cycling, you describe which makes it really frustrating and almost useless when using the grill top or griddle function. It takes some time to warm up these plug ins and then it takes some time to get the food hot enough to smoke and splatter, which usually is just about the time it cuts off, and then when you've taken the food off, voila it starts back up. . . (Most vexing!)
The fan comes on automatically when you turn on the plug in unit with the dial knob. It does not come on automatically when you use the burner plug in piece.
This is utterly frustrating so I simply don't use them. I sometimes use other electric appliances that I set on top of either regular burners if the "set on" appliance feet will sit it flat and not interfere with the spacing of the burner coil or the flat griddle if necessary. That way I can turn on the fan when it reaches ready temp and I put the food on.
The fan will run for continually, without the annoying cut-out, when turned on while using the burner plug in unit, or the fixed burners.
The only time the grill plug in would be worth the bother of putting it in would be if we were all going to have Steaks done "Blue" which is about 45 seconds per side x2 for nice diamond grill marks. But only I like it that rare, and since the BBQ is just off the kitchen door, and hooked up to the house gas, it was easier to use the BBQ. Now that I am on my own, I just use a "grill" style fry pan for my one little steak. I still use a large electric griddle for pancakes and sausages or bacon but since I am careful and use a lower heat &/or the lid, the need for it to be near the fan and thus on the stove top, is no longer an issue.
It's not the solution that you were probably looking for, but it's how I worked around the stupidity of the system/installation.
If there is a mechanical fix, I would be thrilled to know about it! Might be nice to have full use of the plug in when there are more people in the house. :D