Brown Wires from Automatic Climate Control

[73ess]

Troubleshooting the automatic climate control unit in my 76 930 and found these two brown wires at the rear of the unit. Each wire has a male spade connector. Anyone know what these wires are supposed to connect to? I have the Bentley manual for the later 84 - 89 911's, but it doesn't show the two brown wires. Anyone have a schematic for the earlier automatic heat control units?

[Lyle O]

Brown wires are normally ground, so if you look near where the panel mounts I suspect you may see some female connectors with brown wires looking for mates...sorry if I am being Captain Obvious...

[Tom F2]

I have the same unattached wires in my 77, which I bought 18 years ago. They never attached to anything, as far as I can tell.

P.S. Please let us know if you succeed in troubleshooting.

[cpa]

73ESS, Look under the carpeting at the back of the opening there should be two disconnected wires that go to the engine compartment. One is 12v power the other goes to the engine compartment blower. The controller switches on the blower. Sorry I don’t remember the colors.

[73ess]

Will keep looking but nothing so far. So does the controller supply the 12V to the engine compartment blower or does the 12V come from the blower to the controller? If the former, how does the controller get power? And just to confirm, there would be an engine compartment blower in a 1976?

Originally Posted by cpa

73ESS, Look under the carpeting at the back of the opening there should be two disconnected wires that go to the engine compartment. One is 12v power the other goes to the engine compartment blower. The controller switches on the blower. Sorry I don’t remember the colors.

[Tom F2]

A 76 930 does not have an engine compartment blower.

[cpa]

73ess, I'm working with an '82SC that has the same original controller so my information may not be 100% helpful to you. As Tom F2 says if you don't have a blower in the engine compartment then those connections will not be of any use. They are only to allow the controller to turn on the blower that is supplied power from the engine compartment fuse panel thru the controller and back to the blower. They are not the power source for the system. The Bentley manual '78 to '83 has a reasonably good diagnostic process to locate potential problems. Once you understand the operation you can test the components. The controller has a circuit board that has a high degree of potential failure. There are people on the board that can make repairs but you need to do the trouble shooting to see if it is the controller giving you problems. If you do a search for "Automatic heater control unit repaired - 70 cents!" you will find many posts that will help. It is a process. By the way you haven't said what your problem is? Is it not functioning at all or is it not controlling the temperature.

[jeffcavalier]

Hi Guys,

I have a 1979 sc Targa and I have just started looking at the heater controller, mine also has the 2 brown wires but there are two yellow ones hanging loose that go under carpet presumably they are the connections,, also anyone know were the two sensors should be apparently there is an internal one and one in the exhaust somewhere but I can't see anything, Also what do they do ?
Jeff