These all seem to just blow air across the window to dissipate the moisture from the rear window. They also use a resistor wire for low speed. Thru the resistor wire is low, straight thru the other wire is high. Why did they never think to put a small resistance heating element inside the housing to blow slightly warmer air? It was into the 70's before the hot wire grid became the standard.
Bean counters. Why would they build a blower with a heater when they can sell you a rear defroster grid. The grids are just cheap painted on lines that they charge the customer for and probably make more money per cost ratio. That's my opinion anyway!
That's right when things were evolving. I think the big cars were avail. w/a embedded grid def. & stereo. The '72 A-body wasn't supposed to happen so the design efforts had prob. largely moved onto the new model.
I can't remember which car it was, but I did have one with the blower, it wasn't as fast as the newer grid-type, but once you got a little heat in the car it worked acceptably well.
