My 1977 911S Can someone tell me where these wires go?

Orange914-6 · 12-05-2009, 09:46 AM

Under the heater control panel between the seats. Three plugs go to the control assembly, but I found these two yellow wires without a plastic plug on them, can someone help my identify where they go?

moneymanager · 12-05-2009, 10:30 AM

Doesn't look like Porsche to me...maybe some aftermarket thing. Anything not work on your car?

Oh Haha · 12-05-2009, 10:42 AM

Like MM asked, did the autoheat feature work properly?

I've looked in my Bentley but didn't find those wires.

Orange914-6 · 12-05-2009, 10:44 AM

Quote:

Originally Posted by moneymanager

Doesn't look like Porsche to me...maybe some aftermarket thing. Anything not work on your car?

Well the blower for the heater (the one located in the engine bay) is not coming on the way I think it should. I am new to Porsches but I am assuming that the 10 position dial between the seats should run the blower, correct?

The blower does run if I put 12 volts to it directly so I know it is good.

I pulled the controller between the seats out and tested it and found the dial to be faulty so I am looking for one of those. But While in there I did notice the two yellow wires were going nowhere and I was hoping someone knew what they should go.

My first guess was illumination or something but since I'm having trouble locating an electrical diagram for my 77 car, so I was hoping for some help here

Thanks!

Orange914-6 · 12-05-2009, 10:49 AM

Quote:

Originally Posted by Oh Haha

Like MM asked, did the autoheat feature work properly?

I've looked in my Bentley but didn't find those wires.

I don't think I have autoheat, the dial is manual and my car is a 06/1977. Is autoheat a later feature?

I have the assembly apart, but that is the inner assembly on the left side of the picture.

Take a look at the pic:

Oh Haha · 12-05-2009, 10:52 AM

Good job on jumping in to do the repair yourself.

You can find wiring diagrams here at Pelican. I looked there before going to my books.

Atthetop of this page, go to "tech info center" and then to the leftyou will see various items to choose.Click on wiring diagrams and then pick theones for the SC.

Yours will be just aboutthe same, even though it is a 77.

I did a search of this forum but came up with nothing as well.

Oh Haha · 12-05-2009, 10:53 AM

that's the autoheat you have

gsmith660 · 12-05-2009, 10:54 AM

The yellow wires go to a switch on the manual heat levers that I believe turn on the blower motor in the engine bay

Orange914-6 · 12-05-2009, 10:55 AM

Quote:

Originally Posted by Oh Haha

Good job on jumping in to do the repair yourself.

You can find wiring diagrams here at Pelican. I looked there before going to my books.

Atthetop of this page, go to "tech info center" and then to the leftyou will see various items to choose.Click on wiring diagrams and then pick theones for the SC.

Yours will be just aboutthe same, even though it is a 77.

I did a search of this forum but came up with nothing as well.

Thanks yeah I spent all night searching and the closest I cam was a picture but I need more info!

Orange914-6 · 12-05-2009, 11:00 AM

Quote:

Originally Posted by gsmith660

The yellow wires go to a switch on the manual heat levers that I believe turn on the blower motor in the engine bay

Ok, we're on to something....any idea what's missing on my car? The yellow wires have no connector on them at the moment, perhaps it is missing? I did notice the heater lever has a little ball joint on it similar to one on a R/C car but there is nothing connected to it. Please look at 1st picture.

Oh Haha · 12-05-2009, 11:12 AM

The rod should be attached to a servo which raises and lowers the lever as the heat exchanger flapper boxes open and close.

here's a great thread with pics to see what thebits should like:

Automatic heater control unit repaired -- 70 cents!

I cannot tell if the yellow wires you have go to the servo, however.

The Bentley manual appears to indicate a yellow wire attaching to "heater ventilator" switch.

Orange914-6 · 11:37 AM

I think the autoheat is a later system (or at least the servo system). My control box has no circuit board just a fairly simple switch, I took some pictures just now since I have it all apart.

Also my heater lever does have a ball joint on it but it does not attach to anything and I don't think it ever has.

javadog · 12-05-2009, 11:47 AM

Quote:

Originally Posted by vespam5

I don't think I have autoheat, the dial is manual and my car is a 06/1977. Is autoheat a later feature?

I have the assembly apart, but that is the inner assembly on the left side of the picture.

Take a look at the pic:

You most sertainly do have auto heat. It was available in 1977. In fact, it was standard on some cars. The problem that you have is that you may not have all of the pieces.

JR

Orange914-6 · 12-05-2009, 11:55 AM

Ok the reason I didn't think I had autoheat is because my controls are much simpler than the others I see on ebay but it is starting to look like my box was gutted.......starting to make sense.

Flat Six · Flat Six's Garage

Just came across this thread while searching for other autoheat info. In case someone else has the same question, those two yellow wires look like the leads to the temp sensor in the heat exchanger. Provides input to the autoheat module. R&R of the sensor requires the leads to be pulled out of the plastic connector in order to fit through the grommet & bulkhead to the engine compartment. See Bentley 801-4.

Hope this helps someone.

Dale

RoninLB · 12:13 PM

These are from the Workshop Manual. Bentley Carrera also has elec diagrams

The first is labeled 1975 at bottom
The second is from the SC diagrams