FredR

Schocki,

I understand all the body joints on my compresser were renewed [they came in a kit] but I did not check personally. Not sure I would want to run my a/c all the time during a Euro winter but I can believe it helps the system reliability. I have little in the way of option other than the Jan/Feb months.

Your system performance sounds about perfect.

Regards

Fred

Schocki

Just came back from a quick ride with my kids. My daughter complaint that it was to cold in the back (no additional evaporator in my GTS).

Leaving the AC on is no problem. The clutch will not engage at very low temperatures.

dprantl

Correct. What happens is the condenser becomes super-efficient at heat dissipation due to the low ambient temperatures, and the interior of the car will need almost no cooling. If you set the temperature slider to a comfortable temperature and leave the compressor button on, the system will run the compressor until the freeze switch turns it off, which will be quite fast. Then the mixing flaps will mix hot air from the heater core with cool A/C air as necessary. In fact, it is a good idea to have the A/C running during winter as this dehumidifies the air and stops the windows from fogging up.

Dan
'91 928GT S/C 475hp/460lb.ft

Schocki

Very good couldn't have said it better

FredR

Well it seems I have a different problem to what I thought. Took the car down the local a/c shop just around the corner from home- purposefully did not run before hand to protect the tech's hands from the heat.

As the car started the a/c was very cold so decided to skid the a/c shop and a few mintues later the a/c stopped working. Hmm! Loss of gas does not work that way so played around with the on/off switch and back it came. Seems it may be connected to the degraded wiring on the front loom, thaat or the switching gear. either wya, when it was working it was nice and cool so not a gas problem at the moment.

I can swear my late 90 S4 never gave me the same grief but then it never saw its 21st birthday like this one did this year albeit I still think it was better built.

Don't you just love these cars- still it seems to be running quite well.

Fred

Schocki

Question: how old is the AC relay at the controller?

FredR

Now there's a question- I would have to assume it is the original item as are all my relays. As a general statement relays on 928's seem to fare rather well out here- the only relay problem I have had [touch wood- i.e. head] was the light unit relay a few months ago that Alan and the team helped me sort out.

I take it from the question that could be a suspect here? Perhaps I should seek out a spare in my relay box assuming I can trace the part number.

Regards

Fred

Schocki

The symptoms are typical for a relay problem. Use the search function for "ac clutch relay". Dwayne wrote a very good write up about how to change it. You will not find this relay at the central electric or in any Porsche list. It is an integral part of the HVAC controller.

The relay is not strong enough and likes to fail after many years of use. It is a typical 928 weak point.

FredR

Cannot say I have heard this described as a weak point but happy to take your word for it. Presumably pre-emptive diagnosis is nigh on impossilbe. If I remember correctly I suspect this is a difficult replacement as in removing large parts of the dash.

How difficult would it have been to have the relay in the central electrics?

They certainly went out of their way to make this car unfriendly for repairs.

Regards

Fred

j.kenzie@sbcglobal.net

Hi Fred,
No need to pull the dash. The a/c head unit comes out, like pulling a radio. Find Dwayne's write-up and add a relay. Not that hard of a job.
Good luck,
Dave

jeff spahn

Fred. I did the relay replacement per Dwayne's write up. Works great now! Mine is R134 conversion (new compressor, expansion valves, drier, barrier hoses). Mine has no leaks.

Be sure to use Nylog (blue version) on the o rings to ensure a leak free installation. See your local home AC contractor to buy a small bottle of this stuff. Like a lubricant for the o rings.

FredR

Dave,

Must be confusing with something else- when I dismantled my wrecked S4 I depsite all my reading at the time I was somewhat surprised at the number of control modules and relays stashed away here there and everywhere. I will search for Dwayne's write up on the subject.

Does anyone have a picture of the relay and how/where it sits? Doubless I will find from the manuals when I get chance.

Regards

Fred
regards

fred

Schocki

As said before, it's all in Dwayne's instructions: https://rennlist.com/forums/928-foru...re-w-pics.html

FredR

All was revealed- see my post to that thread. Now some diagnostics to do.

Regards

Fred

FredR

Well, whilst messing around with my MAF honey comb and other checks today I did some checking as per Dwayne's write up and the wiring diagrams. could find nothing wrong on the wiring diagnostic front so pretty much assumed it had to be the relay.

With this mind I was in the cockpit contemplting removal of the dash control unit - I then took a look at the temperature control **** and lo and behold it was on the minimum settting. I never touch that switch so presumably a tech at the local dealer must haveb een playing around with it. It was about 34C outside this afternoon when I took the 928 for a spin and it was blowing nice and cool -no problem.

If all else fails read the instructions- durrgh!

Regards

Fred