fan limit control L4064. I was sent on a follow up to replace fan limit switch. The tech that was there before said this prevent the blower from running.Although we are in ac mode. This was in a package unit Lennox GCS16-653-75-51 SN 5691HO1913. Was reading the ninstructions on the control it says must remove jumper on control when used on low voltage circuit.If anyone can explain this please explain or point me in the rght direction so i could fully this control. Any replies are thanked in advance. Oh i repaced control and removed jumper and ac is running.