air con questions

[DanThe]

Tim, the connectors are likely to be for the heater temperature knob.

+1

I think I enquired about a lecy fan loom a couple of years ago, mega money. I would just make one up

[ian332isport]

Tim,

Top pic is the idle speed increase signal to the ECU (should be black/white). It goes to 12v when you switch the A/C on. Hopefully you can get MS to perform this function.

Bottom pic shows that you have an A/C heater box from an earlier car. The white connector plugs into the back of the heater control knob, and controls the heater solenoid valve. The black plug should plug into the rear of the heater sliders. On earlier cars, you could only engage the A/C when the middle and bottom sliders were in a particular position. It was designed to stop the evaporator from freezing up. Later cars don't have this connection, but may have a different evaporator temperature regulator (the large relay looking thing on the side of the heater box) that stops the evap from freezing up.

Regarding dryers. You should be able to use anything that physically fits. If it's r134a compatible, then it should also be okay with r12. You can't however use an r12 dryer with r134a.

No probs running an E36 compressor from E30 electrics. Both are only expecting a 12v feed to engage the compressor clutch. You may have to get funky with the pipework though. The E30 system uses regular threaded connections, but the E36 generally uses a totally different style of fitting. It's a sort of metal block that secures with a single screw.

Cheers,

Ian.

[tim_s]

Thanks for all your replies guys, really helpful. Ok, so for now I'll tuck the 12v for idle speed increase out of the way, that can be used later to rig into the MS or open a valve I'm sure.
Ian, that's some really impressive knowledge! As I have a late car, will the black plug go into my slider ok, and should I do so? What position do the middle and bottom sliders have to be in? Is this going to be a problem, am I better off with a later heater box?
I figure with some of the engine plumbing, if it will be tricky changing compressor, I may just leave that to an air con place, or is that likely to get expensive?
old-skool, do you think I could get some ideas of how to rig up the wiring without having to actually borrow the loom? Would it be too difficult to work out what goes where in order to make a copy loom?
Thanks once again
tim

[DanThe]

I have the early system and its no bother, one of the two lower slides needs to be about an inch across at least. With mine I used the control panel from the air con donor car.
Get the hoses made yourself, its not dear at all as long as you have all the right fittings, I got some hose to the approx size and test fitted it with the fittings jubilee clipped to make sure they were crimped in the right place

[old_skool]

Tim, I think the wiring diagrams that Ian supplied to help me may be suffiecient for the average DIYer to build a replica loom in itself. I still reckon you'd be better off hanging on for one though just for the simplicity of it.

I had an A/C place braze my fittings from the S50 compressor to the old fashioned steel M20 A/C pipes and they took their time, and my money! It's not a five minute job. I know Dan got them made up iirc for £20? Probably best to ask how/what/where with him.

I can tell you after fitting this all to my car and having the aggro of making it work with an S50, knowing what I know now, I would buy a scrapper (easier said than done) with A/C and have the pleasure of taking it out so I could witness first hand, how it went together again.

Best of luck!

P.s. It is all worth it.

[tim_s]

Thanks for all the help and suggestions. Ian, any chance of the wiring diagram?
So I'm pretty much ready to put the heater box into the car I guess. Will use the blower from my existing unit, mb the heater matrix if it fits, and will leave the wiring to the ECU for now. If the heater slider needs replacing for a pre-facelift, I guess I can do this afterwards without the dash out! Anything else I ought to change? Think I'm going to have to move my megasquirt ecu, currently its under the heaterbox behind the centre console bottom bit. I'm guessing there won't be any room with an AC heater box? Expect I'll leave this til after my ring trip at the end of the month.

[Brianmoooore]

The motor and fan blades on an aircon unit are bigger than those in a post facelift heater unit.
For wiring diagrams: http://www.autolib.diakom.ru/CARS2/ BMW, third link down, mitchel on demand, then follow the drop down boxes.

[Alan99]

I have an E36 engine in my E30 which has E30 A/C.

The E30 Compressor is fitted to my engine with an adapter plate I had made.

I'd rather use an E36 compressor bolted directly to the engine block as it should be as
the E30 compressor is very close to fouling the Cooling fan blades.

If I wanted to fit the E36 compressor, what would I need to do regarding pipework and correct (legal) gas?

[DanThe]

You can have the existing pipes modified to fit the E36 compressor

Here are mine

[Alan99]

That's what I thought.

What gas do you use? The newer stuff?

Did you use the BMW exchange kit?