I would like to connect booster fan to the blower motor in my furnace. The blower motor has 5 wires going to it: - Neutral And 4 others: - Cool-H - Heat-H - Park - Park The booster fan is 120VAC and I wonder which wires is it best to connect to? They all get voltage when the the blower turns on. Should I use relay or direct connection will be better? The furnace is Trane XR90.