A/C question, I know it's Feb here in Chicago....

[84 911 WideBody]

I have to diagnose my inop A/C on my ’84 911. Since I don’t have an owners manual or a repair manual at this time, I have operation questions. First the two control knobs on the center console, the one for fan speed, I am assuming condenser fan. Will this run if the compressor clutch is not in gauged? Again the assumption is the knob on the left is temp control for the A/, is there temp sensor? What is the strategy to operate the A/C clutch? What is the rheostat control that is in between the a/c control knobs for?

[rick-l]

The switch turns on the fan by the evaporator. If you turn it on you should hear it.

In my 88 there is no low pressure cutout switch in the circuit so it runs whenever the switch is on.

The switch in the center looks like a speaker fader control(???).

[ruf-porsche]

You need an electrical diagram of your car to determine if the condensor fan will engage if the compressor clutch does not. On my 82 Targa there are two relays that engages when the ac switch is turned on. You can spend big bucks and buy them at a Porsche dealer or you can go to Rat Shack and pick them up really cheap.

You will need ac equipment such as ac gauges to diagnose your ac problem. Replacing parts can be expensive.

Hey you live in the suburb next "It's not gonna happen", but with the new season just a couple of months away and the fact that the CUBBIE are picked to repeat as Division winner this year who knows?

[Barrpete]

The knob on the right turns on the AC evaporator blower fan in the smugglers box. It also engages the AC clutch. The evaporator fan will run independent of the compressor. The knob on the left is the temp control, there is a capillary tube filled with a gas that runs to the evaporator and will cycle the compressor clutch on/off depending on the temperature.

The rheostat in the center is the fader for the stereo.

[84 911 WideBody]

I dont through parts and anything. I am an instructor for Navistar and have done the same for GM and Bosch. I have access to any and all a/c diag equip. One of the perks of the job. I just need to know the functionality of the A/C Diag. it properly.

Ruf, We will need to get together and tip a few if your that close. I am right over here by Winston park. I also get out and Run with Souk and his ChicagoLand Porshce group on yahoo.

And the Cubbie's.....Well will see.

[ruf-porsche]

Here's a link to the ac electrical diagram. I know this work with my SC, but I don't know if it is still valid for a Carrera.

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_82SC_AC.jpg



From the diagram it appears that the fan for the front mounted condensor is only on when the compressor clutch is activated. If you haven't install an in line fuse for the front condensor fan I would suggest that you do that. I had an Audi Quattro that burn up the wiring harness because the radiator fan seized and there wasn't a fuse for the fan so the wiring harness became the fuse. If you do a search on this forum you will find other owners that had their cars catch on fire because of the fan seizing up.

[Goth]

Originally Posted by Barrpete

The knob on the right turns on the AC evaporator blower fan in the smugglers box. It also engages the AC clutch. The evaporator fan will run independent of the compressor. The knob on the left is the temp control, there is a capillary tube filled with a gas that runs to the evaporator and will cycle the compressor clutch on/off depending on the temperature.

The rheostat in the center is the fader for the stereo.

+1 on above. That's how my 84 Carrera works.