Here is a pic of my 61 suburban.
Great thread!
Thank you markeb01 for pictures of you manuals... helped me figure out where the plug from the fan switch to the fan motor needs to go. I thought something was missing on my rig, looks like there is a spot on the back of the unit in the cab to plug it onto. Might be why my fan is either on or off out of the 4 positions. After plugged in, maybe the fan will have off and then 3 speeds.
Great picture of the auxiliary heater for the suburban aerotruk63, I would love that in mine to warm up the larger space in my suburban. It get kinda chilly in Sandy Oregon.