I finally figured out how to get the grids on a switch. By utilizing the positive wires that energize the grid heater relays, you are able to take control of when the relays energize. To do this, all you need to do is put a switch somewhere between those wires so that you are able to close or open the connection and therefore keep the relay from energizing. The two wires you will need are the orange and black one, and the yellow and black one. The other 2 wires are green and are the ground. You can switch either one, the ground or the positives. I chose the positives because I only used one switch. Having 4 batteries, I do not see the need to only be using one grid, so I connected both positives together so that when just one energizes, it still energizes the other so both grids always turn on. This has a drastic effect on how long the grids stay on during the on/off cycle after the truck starts, they only stay on for half as long since they have twice the heat output. For all normal purposes however, I would use two switches OR you can connect the grounds together (which connect together upstream somewhere anyways) and use just one switch that way, and the grids will stay seperate (they will each turn on individually instead of the way I have it set up). I am not sure if 1998+ trucks will throw a code, there are many codes listed but I can exactly find one that will trip for this very isntance, someone with 1998+ will have to see. Trucks 1997 and below will not throw any codes.Here you can see the voltage drop a lot since it uses both grids every time.

Is it normal for the IOD fuse to cause a pulsing like that? I pulled that fuse and the test light went dead. I will figure out exactly how much amperage is being drawn through that fuse.

Probably power for the radio/clock

Ok. Without anything plugged in in the cab there is only .008 amps being drawn through the IOD fuse. I plugged my stuff back in (i.e. cell charger, radar detector, etc) and it came up to about .15 amps being drawn from the batteries. Not enough to bring them down over night I wouldnt think.