Aircon help

zwhitea · Apr 18, 2004

Help need from you out there with Aircon fitted...

I am currently trying to rewire parts of my 1987 911, and as summer is on the way its time to sort out the Aircon... However the previous owners appear to have totally messed a few things up...

Can anyone help with the what looks a 4 pin plug.. I could do with knowing which pin is which and the colour of the wires etc....

Any chance someone can stick their head in the passenger footwell for me...[

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Also other than a breaker yard, any idea where I can source a plug, and or part of the wiring loom etc...

thanks Adam.

Guest · Apr 18, 2004

I have a/c in my 87 3.2, but can't say that I recognise the bit (mind you, it seems a bit unclear).

I assume that the pins are like those on the base of the relays (they look round, and spaced about right). What is the metal 'pipe' that the female part is attached to - it seems to be part of the heating ducting.

If you can give me a bit more info, I can look it up in Bentley, as that has a large section on a/c wiring (more pics ?).

Either post here, or email me.

zwhitea · Apr 19, 2004

John,
I not sure but I believe it is part of the Evaporator, but I can't be sure. I have tried looking in the Bentley book, but it just makes me think I've possibly got some form of bodge/after thought..
The evaporator unit is mounted in a housing in the passenger side footwell, where as in the Bentley book, it is somehow mounted and accessible from the boot, under an access panel.

There are 4 round pins, which from the current mess, only 3 had wires connected.. One which went to the AC fuse, another which looks like it goes to the AC relay.. and another I'm still trying to trace...

If you can shed any light on this it will be a great help..

Guest · Apr 19, 2004

I've had some of this apart on my 3.2 but I can't recognise the item in photo.

Maybe if you could take another pic from further away so we can get an idea of the orientation of the first pic.

The Bentley manual is for left hand drive where the evaporator is housed in the compartment just in front of the right hand footwell (this is usually called the smugglers box). It is accessed from a door in the luggage compartment.

I don't know if the right hand drive evaporator is the same one as for the left hand drive so Bentley may not be much help here.

Cheers

Andy

Guest · Apr 19, 2004

On right hand drive cars, the evaporator is accessed by removing the wooden board that the passenger feet rest on.

Oddly enough, my car was having it's refrigerant replaced today, after it had slowly leaked out (detected by thin film of light oil on the leaking joint).

I will try to look into this area tomorrow - and I agree that a bigger picture would be useful to see where I should look.

Guest · Apr 19, 2004

Interesting, my car has the Behr petrol pax compartment heater in this 'smuggler's box' cabinet (prefer using the doors myself) and air con as well so wonder where the evap is...must have a look, will see if I can spot this 4 way plug too

zwhitea · Apr 20, 2004

Thanks for everyones input so far... Hopefully this picture will help you see my problem...

From doing some more digging in the Bentley book, I suspect it maybe something to do with what they call Bimetal Switch..?

Guest · Apr 20, 2004

That's much better. I can now see the top of the evaporator, so know where to look on mine.

It looks like something has been pressing against the top left fins on the evap. unit - this is often the wooden board that covers it (it was in my case). Don't worry, they are very expensive to replace, if they leak !

Having said that, I assume that the large pipe with the male connector on carries the chilled air from the rear of the evaporator to the dashboard vents. If so, then I don't think that mine looks like that.

But, I have printed the picture, and will look at my set-up tomorrow.

zwhitea · Apr 21, 2004

Thanks John, A picture of what your system looks like would be interesting as well...

As for the damage, the old board, before a changed it had a big bolt pressing against the unit... There are some real muppet owners out there..?! I think I may have got away with it as it looks like its just the fins which damaged and not the pipe work... Will have to wait and see what a pressure test shows...

Once I have got all this sorted I still have to find someone to convert the system to the modern gases.. What this is going to cost me heaven knows..

Still what else have I got to throw money at... other than that super-charger I want [

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Guest · Apr 22, 2004

other than that super-charger I want

No, you don't want that - all the whistling on boost, and chattering when the 'waste gate' cuts in, and only 300 odd bhp; who could need that in a 3.2 ?! And no turbo lag, and the chance to confuse a 930 (more power, less weight).

I had a look at my Bentley book, and have come to some conclusions.
Sorry if Grannies sucking eggs come to mind, but best to start simple.

The bi-metal switch should be in the intake pipe to the evaporator; according to the wiring diagram, the bi-metal strips (2) should short out their matching resistors, so that, for example, if the fan switch is on 1 (lowest), and the cabin temperature rises, the low bi-metalic switch will operate, bypassing the respective resistor, and switching it to the higher setting (position 2) etc.

It would seem that the pipe in your case runs to the back of the evaporator, and that the front is bare - this is like mine. Having the switch on the rear, so that it monitors the chilled air, does not seem to make sense (OK, so I could be wrong here !).

Mine does not have an automatic fan speed switch, just the normal manual one, so it seems that I don't have this bi-metal bit. Also, not having a digital camera (modern technology has largely passed me by), I would find it difficult to take pictures quickly (have I no friends ? You may well ask).

So, my next step is to check my wiring/set-up (which I meant to do yesterday, but went to Staines instead - a poor excuse, I know).

So, I will return.

Guest · Apr 22, 2004

At last, I have taken my air-con apart (well, the area around the evaporator), and have got some answers.

My air-con does have the bi-metal fitted (I don't know if it works), but it is on the front(front of car)/underside of the pipe that comes from the rear of the evap., the one that carries the cold air to the vents. So, the same general pipe as yours, but with the plug/socket hidden in my case - different pipe, I suppose. I found mine by running my hand along the back of this pipe, and then pulling the free socket off.

The free socket (the pipe carries the fixed plug) is square black plastic, with a clip-off back, and 3 heavy cables going into it; the socket case had no part number on it, just Made in Germany, and the letter K. I removed the back of the socket, and here are the positions of the wires.

If you view the free socket from behind (individual female sockets away from you), and the cables going down (south), then the 3 cables relate to:-

red/white stripe - top right (north east)
red/black stripe - bottom right (south east)
red/green stripe - bottom left (south west)

(Pictures, who needs pictures ?)

According to Bentley (using their colour-code), these are the cables that go to the bi-metal switch, and they also connect to the rear of the 3 posn. air-con switch. In my case, this is in the centre console, alongside the air-con thermstat. Having studied the diagram again, I must have the bi-metal, as this is the only way that the system can work - but no variable rate (perhaps mine is too efficient !)

As an aside, I have modified my passenger footboard, by removing some of the wood on the right, and replacing with a wire mesh cover (painted black), to allow more air to get to the front of the evap., and hence get better cooling.

I hope that you followed all that, particularly my use of plug/socket terminology - any more help, just let me know, either via the forum or email. Don't suppose that you are near me, just in case. At least I understand car electrics.

zwhitea · Apr 23, 2004

Thanks for all your help john... I suspected it was teh Bimetal switch, but wanted to be sure, becuase there is not much info for UK cars with AC... it all appears to be for Lefthand drive cars...

Hopefully when I car my car back from being serviced, I'll be able to sort out this part of the wiring... which will only leave me another few miles of previously installed mess...

Thanks again.... I'm sure I'll be posting more enquiries for sorting out the wiring later, if I can't work it out from Bentley or Mitchell On-Demand System.