914-6 Rear Window with Defogger

[Turboman]

I want to add to my 914-6 (1970) a rear window with defogger.
I do have the rear window and the correct switch.
After a week looking at the manuals and all my related literature, I have not a clear idea "how to wire the defogger"
I found on my Factory Manuals that I need to use a relay on my main board. Unfortunately, I only have two relay positions on my main board and both are on use.
Some one with a clear easy diagram I can use as a guide?
Thanks in advance.
Francisco

[porschetub]

Originally Posted by Turboman

I want to add to my 914-6 (1970) a rear window with defogger.
I do have the rear window and the correct switch.
After a week looking at the manuals and all my related literature, I have not a clear idea "how to wire the defogger"
I found on my Factory Manuals that I need to use a relay on my main board. Unfortunately, I only have two relay positions on my main board and both are on use.
Some one with a clear easy diagram I can use as a guide?
Thanks in advance.
Francisco

Hi,there are 2 boards for the 914/6 as far as I can tell and I believe it was a model year dependant,1 board has the relay pins,you would appear to have the board without this 3rd relay pins,for this application the relay was located in the loom....where I don't know,if its not there maybe this wasn't an option ordered when your car was new.
It really would'nt be to much hassle to wire one in,as far as I can see it maybe your only option.
I have a demist type rear screen and no wiring on it...sucks.
Good luck.

[Steam Driver]

Question: why bother other than to say you have it? Back in the '70's I lived in Kansas City where (at that time, not so much recently) we had a lot of nasty winter weather. I had a '70 914, and later a '70 914-6 (I had the latter for 18 years) for my daily drivers and because of the sheltered and back-slanting configuration of the rear window I can't ever remember needing the rear window defogger option, nor ever having to scrape the rear window. So there a reason that's a rarely-seen option.

Now if you just want it for brag gin' rights, that's another story.

[porschetub]

Originally Posted by Steam Driver

Question: why bother other than to say you have it? Back in the '70's I lived in Kansas City where (at that time, not so much recently) we had a lot of nasty winter weather. I had a '70 914, and later a '70 914-6 (I had the latter for 18 years) for my daily drivers and because of the sheltered and back-slanting configuration of the rear window I can't ever remember needing the rear window defogger option, nor ever having to scrape the rear window. So there a reason that's a rarely-seen option.

Now if you just want it for brag gin' rights, that's another story.

Think the OP wants it working and I guess I want the same for mine?,are you saying they don't work very well or you stuck on" bragging rights" thing.
Surely the inside must fog up somewhat @ times...just asking .
Personally if you have a car you like isn't it nice to have things working ?,cheers.

[Tobra]

He is saying you don't need it due to the way the rear window is protected from the elements, both by the sail panels and the rear of the top. I know a guy that will probably know the score

[Turboman]

I never had the idea to generate a debate on this forum.
Searching more carefully thru my Service Manuals, I fund a diagram for 1994 model.
My 1970 914-6 have a different relay board, but I feel I can do it.
Nevertheless ideas are welcome.
Keep all of you posted.
Francisco

[porschetub]

No, not that way @ all ,not interestested in starting a pissing contest,but was merely asking why it is not required ...Porsche put it there for a reason,they have never been a company to add useless stuff...mostly.
Funny got home today after some recent bad weather and noticed the inside of mine was fogged up....

[Cairo94507]

My last 914-6 (1970) had a defroster rear window and my '71 will when it finally goes back together. I like the look of the defroster window and it was an option, so it will be installed and working. On my '70 I can count the number of times I used it on one hand, nonetheless, I like them.

[Turboman]

Cairo, If you have the opportunity to look a the loom, please let me know the color of the cables. Thanks
Francisco