I have a '71 442 with factory rear glass electric defroster (grids in the glass). I've never seen this on an older car (I only knew of the blower motor type under the package tray). Is this a rare option and any way to determine how many with this option?

 

That is a aftermarket add on. Did not use that type in early 70s.

 

It's probably not that rare for northern cars and likely near impossible to find out how many were equipped.Most Canadian Cutlasses had either the blower or the electric grid type by neccessity.

 

It probably was not a factory option, but I am not sure. If it looks like a stick on grid with side lines, it is probably a JC Whitney special. However, I think Gran Prix's and some others had factory grid defrosters in those years and the glass may be interchangeable, so someone may have added it. I remember people doing that with Chevelles as I think the rear glass was the same.

 

Years ago I saw a 1972 4 door Cutlass that had what looked like a factory setup. Someone should have a list of what options were available in 1971. What does the dash switch look like? How is it wired in? If aftermarket the switch and wiring may look like an add on. John

 

No it's a factory option (on my order sheet and build sheet). It even describes it in the Owner's manual and is part of the A/C control panel. It was a Canadian imported car so I can understand choosing that option but I would assume it's rare as most people have never heard of it.

 

You could get either electric grid or blower type on the A-body car starting 1970 or 71. The electric grid type was exclusive to the E-body car starting 1969.

As far as how many 1971 were built with it, anyone's guess. But I don't think you'd commonly see either type back then. It was one of them gadgety options that generally appealed only to people who wanted a fully optioned car or someone who lived in cold climates. A useful option, yes, but most folks didn't see spending the extra money to get it.

The control switch is integrated into the heater/AC control head. Grid type had a red indicator lamp to show when it was on and had an "on-off" switch. Blower type had a "lo-off-hi" speed switch with no pilot lamp. Switch was adjacent to the main blower speed switch. The grid type also incorporated a timer to shut off the defog after (I think it was) ten or fifteen minutes, as the thing drew a lot of power. Cars so equipped would have had a 63 amp alternator. I know that by 1974 there was also a cutout relay that prevented high blower speed with the grid defogger energized. I'll have to check the manuals to see if that circuit is in the earlier systems.

 

Sorry, you're wrong. It's a factory option C49 and could be ordered with tinted or clear glass. This option was available for fastback and Supreme models.

The "stick on" grid work you're describing is not the same as the one mmurphy is describing. You're right that the rear glass can be interchanged on some models, but the Cutlass fastback does not share its rear glass with any of its stablemates. Most dealers would install the blower type defroster if you bought a car without one. The term "defogger" is used for electrically heated rear windows, and "Defrost" was used for forced air units.

You're right and your documentation will prove it. It didn't have to be Canadian ordered to get the defogger unit though. I would be curious to know if the code I have in the SPECS guide is correct. It lists the option as C49. What does your buld sheet list? Back in 1978 I removed this option from a wrecked 72 Cutlass S and kept it to install in my 72 Cutlass S . I had to take the front and rear seats, and rear inside trim off to get the wiring harness. There are 2 attachment points for the wiring harness at the bottom of the rear glass for the current to the defogger. This option is high draw, and I also had to get a 63 amp alternator (mine was originally a low option car with a 37 amp). The dash escutcheon has 2 levers on the right side of the heater controls. 1 lever is for fan speed. The other lever is labeled "defog" and is 2 position - on / off. Between the 2 positions is an indicator lamp that lights up when the defogger is "on". I beleive it's there to remind you to turn the unit off, because it does NOT shut off outomatically. That was later technology and the timer was based on a command signal from a spring loaded contact switch. The car could also be ordered with the rear defroster in which case the 2nd switch would be labeled "defrost" and there would be a 3 position switch labeled "off" "low" and "high". I'll dig around in my pic files and see if I can get some that show this variation. I know it's been discussed on CO before and there are differences of opinion on what I'm posting.

As far as knowing how many cars have this option? Record keeping wasn't a strong point for Olds back then. Since you have the broadcast and build sheet, you don't need much else from GM. Although, GM does still have a section for Vintage vehicles for others who have vehicles that were originally built for export to the Canadian market.

 

71 was the first year.

My 70 has a rear window defogger, but it is the blower type.

The 71/72 heater controls have a small red light that glows when you turn the defogger on.

70 cars do not have that.

 

My Framingham built 442 is equipped with a heated back window. Anyone know what kind of adhesive GM used to attach the braided wire to the glass?

 

Good question. Probably need to ask a glass shop. They deal with replacement heated glass windows all the time. I'd be willing to be any adhesive they use now is way better than the stuff that was used in the early 70's.

 

Grid style starting in 71 not rare at all in the northeast. I'm trying to remember if I ever saw a 71/72 "fastback" or Supreme that DIDN"T have a grid style defogger! Appears to me neither with or without would be unusual. Probably more related to the region in which the car was originally ordered. I have seen 70's without any defrost(blower) option but couldn't say what their regional origin was.

The pigtails appeared to be soldered to the grid material that was bonded to the glass. Managed to resolder 1 or 2 & failed to have success on others. I think they make a conductive adhesive now that can repair the connection.

Red 70 in pics had no defroster so we added one during resto w/ OE parts & correct switch. IIRC the switch & a new face decal/applique could be added to an existing non defrost/defog heater control if need be. It's kind of a stand alone circuit & switch.

 

Thanks. It's listed as option code C49 on my docs. Also it must not be working as the LED does not come on when switched to "ON" (something I'll have to look into).

 

Mike,
Where was your car built?

 

Lansing, MI.