H Series, How to Keep Top Vent Flap Closed But Still Run Rear Exhaust Fan?

Trying to figure out how to run the rear exhaust fan on my H2S but have the top Vent Stay Closed.
I’d like to be able to run the rear exhaust fan to remove fumes while printing ABS but keep the top vent closed.
I do not need active heating as the heatbed provides plenty of heat for the chamber.
I have also found that if you run the rear fan in cooling mode, the top vent opens and even at a fan speed of 20% you lose a lot of heat and also the cool air coming in can start the print to warp/lift from the bed.
I can run the rear fan on my X1C’s at 20% and the chamber heat stays constant and no issues with warping for ABS. Would like to do the same on the H2S.
I think if I can just get the top vent to stay closed this will work fine.

H2D have a much more powerful fan and you will probably ruin you print. Besides that you can’t activate the exhaust fan while in heating mode.