Hello all, Please and thanks in advance. Heater box is from a 78 charger. I am puzzled by how to wire in a universal 4 position blower speed switch. Resistor is shown. Cannot find a wiring diagram newer than 76. It does not match. On RH plug. Top (brown w yellow) runs to nothing. Just a female butt. Middle RH(bright green) runs to OE speed switch. Bottom RH (black) also runs to OE speed switch Left upper (tan) runs to OE speed switch, bit also appears ran to a 12v fuse on fuse box. Left bottom (green w white) runs to a stripped end. Blower motor hot appears to be green with no tracer I'm a little lost on this one...any advice?