Anyone have a picture of this unit in your car or a scan from the assembly manual? My manual is a reprint and it is not shown in it
70 is a different unit then 71-72. They changed the panel behind the seat, so the defroster also had to change. Duane
Never knew they put one in a convertible, I don't think they did, I've never seen anything in the sales literature to even indicate that it existed for convertibles. I wouldn't know where to locate it, the unit would be in the way of the folding top. The blower was available for all sedans and coupes (pretty much standard equipment here in Canada) up until the wires came into being, and about that time (1974-75) I started seeing them on glass convertible windows.
very rare to see a rear defrost in a conv but they did do it option code on my 72 gs350 conv is C50 rear window defogger-blower type. in 72 they only made 56 out of 852 johnny
"Never knew they put one in a convertible, I don't think they did, I've never seen anything in the sales literature to even indicate that it existed for convertibles. I wouldn't know where to locate it, the unit would be in the way of the folding top." They did install them in Convertibles. The unit fit in between the rear seat top and the well liner. The well liner was cut and the deflector grill actually blew air onto the rear window from behind the seat. I had a complete unit for a 71-72 GM A-body car. Duane
I believe that there was a special ducting for moving the air from the mounting position of the blower to the special grate or grill mentioned in the previous post. Here is a pic from a different thread of the dash from a '70 GS Stage 1 Conv. with the rear defroster option (and dash plate):
I have a 70 and a 71-72 convertible defogger unit. I also have one installed on my 71 convertible. They are very rare to find. The 71-72 unit could be used on a 70 but not the other way around. As Duane said the 71-72 was formed different to maneuver around the vent..
Anyone with a convertible back in the day during a hot humid thunderstorm can appreciate that option when you couldn’t even put down the window an inch due to no rain gutters. A truly miserable experience.
I have a 71 Skylark Convert with the rear defrost option and it still works, I was driving it around for a weak or so hearing this low humming noise and could not track it. I thought the switch only had a high and low setting, was driving me crazy until I realized when you set the switch in the middle it is actually off - did that, humming stopped - doh.
...another great thread for detail geeks... ...how did Buick handle switches for convertibles with cruise and rear rear defrost...
That's the rarest of the rare Accessory plates. The little green square cruise control fiber optic 'ON' light was right in the middle of the plate with no script or wording (like the cruise only plates with the single little square in the center of the plate). I have only seen a couple of them. My hardtop GS has cruise control and rear defrost, so it just has the square light and the bottom switch for the rear defrost. The real "pinch" for Buick was in '69 when there was an On/Off switch for cruise control (when so equipped) and then in a convertible, there was a switch for the conv. top motor (I believe labeled 'Accessory'). In a hardtop, that same 'Accessory' switch was reserved for an option like the power antenna. But in a convertible, when equipped with Cruise and the power antenna, there no room for an 'Antenna' switch. So, Buick placed a little switch to underside of the upper bezel of the radio surround (looks like a common Olds switch) marked 'DN - Antenna - UP'. In '70, the power antenna option was dropped (I believe it was the first year for the antennas embedded in the windshield glass) and the same location was used for the 'I-2' or 'J-2' forced air vent option.
rear window defoggers were mandated in Canada under federal law to be standard equipment but I do not know when. I know my '70 Chevelle had one and I did not order it.
If anyone has a picture or two of this installed on your convertible, please post or send them to me.
I thought I had a picture without the pad installed but I cannot find right now. Anyway I posted a couple. Nelson .
