Heated Rear Window

[DOUGS73E]

Starting a thread on the subject of heated rear windows based on comments on 911GP's thread:
http://www.early911sregistry.org/for...m-for-1973-car

So, the question/discussion is:
1. Does your 911 have a single-stage or a dual-stage heated rear window?
2. Clear or tinted windows?

^^^^^^^^^^^^^^^^^^^^^^
(Referring to Richard Newton's [Gearby] COA below)


Gee. they couldn't even get it right back in 1990.
"heated rear window, 1 stage, clear" I don't think so!
At least, you didn't have to pay for that.

Regards

Jim
Fan of wheel arch trim

I don't understand Jim. My '72 has clear back glass with single stage defrost. I must be missing something obvious?

I just looked at about 50 single stage, clear, back glasses. I guess, not all of them could have come from 69/70 cars. Am I to assume that clear glass equipped cars came with a single stage heated glass and tinted glass had dual stage? That seems to be the case. I sell so few back glasses that I figured all of them were dual stage after 1970. That is, apparently, not the case.
The major portion of US delivered cars came with tinted glass, which is an option.
Why would clear glass be listed on the COA when it was not an option?
I don't understand, either.

Regards

Jim

It is odd that they even mention clear glass since my COA doesn't list clear glass. I thought clear glass was the standard and tinted was the option so COA's shouldn't even mention clear glass I wouldn't think. My car came with clear glass probably only because it is originally a Portland, Oregon car. We are sun challenged up here . My defrost switch only has one pull outward which is why I figured it was single stage. I guess I'd have to check the date on the glass. Maybe all the clear glass was made prior to 71 but they had a stock of them that they continue to use as clear glass became less and less requested? I didn't even know there was a date on the glass?

Time to start a thread about back glasses and not hijack this thread.

Ciao

Jim

[DOUGS73E]

My '73 911E coupe with a build date of 5/73 has clear glass and a single-stage (9 horizontal wires) heated rear window.

My assumption would be that the single-stage heated rear window remained available through the '70s 911s (including impact bumper models) until Porsche discontinued clear glass windows. I don't know what year all Porsche models came standard with tinted glass.

[Jim Breazeale]

I have determined that all clear glass equipped cars came with a single stage rear glass. I came to that conclusion by looking over my inventory of over 100 rear glasses. I could not find a single clear glass with a dual stage heater. All tinted back glasses were dual stage after 1970. I never realized that. It is a mystery to me why a single stage clear back glass would be listed on a COA or a Kardex when it is the standard part, though. I still discover stuff that I never realized due to this forum. I'll keep reading and learning.

Regards

Jim
PS: The heater elements in tinted back glasses are a yellow color. The heater elements in clear glasses are a brown color. Never paid any attention to that, either.

[Chuck Miller]

April '73 - Tinted glass - Dual stage defrost......

cm

[ejboyd5]

My newest Porsche is a '69 so I don't have a clue as to what is a "dual-stage" rear window.

[edmayo]

Refers to the number of heating wires in the glass. Single stage had 8 or 9 wires across the center of the glass, dual-stage had more wires from top to bottom, it clear more of the glass. I'm sure you're 69 had electric defrost back glass.

[Jim Breazeale]

Your car would have a single stage heated back glass whether is is clear or tinted. Ed is correct. The dual stage windows have heater wires covering most of the back glass from about 4 inshed from the top to 4 inches from the bottom. Single stage windows have heater wires only covering about 1/3 of the glass.

Regards

jim

[Richardnew]

Now I have to go look at my rear window. Thanks a lot Ed.



Richard Newton
Have You Run Out of Money Yet?

[damsroy]

73E, May 73 built, tinted Windows, dual stage dear window.

[Jim Breazeale]

Now I have to go look at my rear window. Thanks a lot Ed.



Richard Newton
Have You Run Out of Money Yet?

Richard

Tinted glass (which would have come with a dual stage heater element) is part of the "Appearance Group". Please let us know what glass you have.

Regards

Jim
PS: Pull your back glass heater switch out and see if it has 2 positions, too.