![]() |
911 Targa, changing rear defogger from two-way to single?
Hi,
I'm replacing my old Targa rear window (with an antenna hole) for a nice newer rear window from a 1986 Carrera. But, that window has more wires to the rear defogger, and I'm guessing it has a two-way (or do you say two-stage?) defogger. So, my question is how I can connect my old wires (just two) to the new window with four wires? Anyone that has done this already? Regards, Johan |
Quote:
If not pm me. Good luck, Gerry http://forums.pelicanparts.com/uploa...1281369828.jpg |
Thanks, what a great forum this is! I just have to figure out how that compares to the wire harness in my 1973 911.
Do you know which one is the second stage? I figure that I only need the maximum one. !s the first stage just lower voltage or every other thread? Thanks, Johan |
Quote:
|
My rear-window defogger is not connected at all. Were on the window can I locate the wires?
|
Remi,
The connectors are on the edges of the glass, under the rubber gasket. There is a wiring harness that connect to the glass, pass through the gasket to a connector near the electric relay panel. Johan, Your ’73 should already be equipped with the rear window ‘relay’ controller. If not, the connector should be in the relay panel. If not, you can find a used one. It is best to use the controller. The heating elements are fairly powerful and should not remain at full power when warm. The controller helps prevents overheating and consequent plated wire failure. Before you install your new window, carefully measure each wire for continuity. You can do this by applying 12V power to the window and measuring the voltage in the middle of each wire compared to one terminal or the other. If you have continuity, the voltage will measure about 6V. If broken, the voltage will be 12V or 0V. Best, Grady |
Thank you for answer. I have a 71 mod.
Is there simply 12V directly to the window, on/off, or is there a controller,? Is it supposed to have the wires running to the relay panel on the left side of the engine? |
Quote:
Here are a few answers to your question(s). Why Porsche designed such a strange behavior for the 911/964 two stage defogger is a question that begs an answer. The 993 models incorporate 15 minute on/off behavior (993-618-117-00). The 911/964 models (1978-1992) are P/N 911-615-115-00. As per the attached schematic, and technical bulletin, Relay #1 (the center element) remains activated when the defogger switch is pressed. Relay #2 activates the upper and lower elements and stays activated until the the voltage drops below the minimum requirement of 11.0 Volts. And, as you can see, only two wires are required to run this circuit, as the upper and lower elements are in parallel. The ground wires location is a 10mm stud on the left side of the engine compartment. (G414). Hope this helps, pm me as needed. Good luck, Gerry http://forums.pelicanparts.com/uploa...1284147724.jpg This note is from Hella. http://forums.pelicanparts.com/uploa...1284147787.jpg This jpeg is my troubleshooting the circuitry. http://forums.pelicanparts.com/uploa...1284147985.jpg Picture of the relay. |
All times are GMT -8. The time now is 02:17 PM. |
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website