924Board.org

jdub · Joined: 04 Mar 2014 Posts: 72 Location: AZ

[No response needed anymore- see the bottom note]

>
I'm about to tackle the disconnected AC after outting te belt back on, what appears to be a newer AC Compressor.
1. under the car at very bottom if an AC hose there is some kind of a green switch with 2 black wires coming out- mine are clipped off. can it stay that way later when i get it charged? connect the wires together or not?
Where would they go to correctly?
2.
Ive done some ac charging and jumping compressor on newer car, but...
I cant find a diagram or tutorial for this car. Anyone have a decent link?

its R12 still i'm assuming

Thanks!!!💂

UPDATE after I posted this:
After trying to charge system, there is probably a restriction in a valve, and the clutch started to make noise, so I quit. I'll leave this alone until I want to replace things. (but I left this for those who were wondering about unanswered Qs)
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81 924 non-turbo

larchie · Joined: 19 Jun 2003 Posts: 297

This 1979 current-flow diagram for the Nippondenso might help, but I don't see a switch with two black wires in the circuit. I doubt that you can find R12 anymore even if you had EPA certification.

Nippondenso Air Conditioner 1979 Porsche 924

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

Is this a factory a/c system? That might be the pressure switch, have a pic? Are the "cut" wires spliced together?
Are you sure there is pressure in the system?
You can still get R12, there are ways.
You can use 134A but the rubber lines meant for R12 have larger pores that the smaller 134A molecules can escape though, this means you will have a to charge the system more frequently.
You will also need to change the compressor oil.
If the system has been empty for awhile you may also need a new receiver/dryer.

larchie · Joined: 19 Jun 2003 Posts: 297

There's also an electrical diagram for the 1984 Porsche 944 air conditioner linked on Pelican Parts' Porsche 924/944 Electrical Diagrams page.

jdub · Joined: 04 Mar 2014 Posts: 72 Location: AZ

ok thanks this will get me started,

had something come up tonight but i hope to start tackling it tomorrow eve,

i will try to get a pict of that sensor or switch right on that lower hose line
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81 924 non-turbo

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

You didn't say if the cut wires were wired together. Is the switch in the line or on the compressor?

jdub · Joined: 04 Mar 2014 Posts: 72 Location: AZ

hi
the sensor switch thing is on the hose/line, and they are separatE (and cut), almost like a thermo temp switch on the radiator (except this is probably some sort of pressure switch i would guess)
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81 924 non-turbo

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

That is a pressure switch. If its between the compressor and condenser, its on the high side and therefore is a high pressure switch. A high pressure switch shuts the compressor off in the event that system pressure is too high.
On the "low side", there is a low pressure switch. The low pressure switch shuts the compressor off in the event system pressure (not enough refrigerant) is too low. This ensures there is enough refrigerant to carry oil through the system to save the compressor from damage. This is the switch you "jump out" to male the compressor run.
Have you determined if this is a factory system?

jdub · Joined: 04 Mar 2014 Posts: 72 Location: AZ

okay, i just back on this, sorry i had a girl graduating

It IS a 134a system, newer compressor! (Tama - japa)

the clutch engages on the compressor- the wire was cut, so i jump tested it directly to battery + , and the clutch engages with no strange noises.

However, there is no cooler air, so I will be getting it charged/gauged shortly when my neighbor gets back.

SWITCH/WIRES - Where does compressor's trigger wire go?
1. Where will the + trigger wire go to when I connect a new wire? I assume right into the relay terminal inside car. But, is there a place I should look where it would've entered the car? I may be able to connect there.

2. Presure Switch wires:
this picture is of the switch on the line from the a/c radiator/condensor to the compressor - so it must be a HIGH pressure switch (and that line is where I'll connect the high on my gauge)
See the cut wires.
[url=http://i1143.photobucket.com/albums/n629/jefforstacyw/photo.jpg[/url]

(the other line is going from the compressor into the firewall, so that must be the low side.)

Where would the pressure switch wires go?
I do have a trimmed NEGATIVE ground wire also on the body of the compressor.

[img]
[url]http://i1143.photobucket.com/albums/n629/jefforstacyw/photo.jpg[url]

tHANK YOUUUU
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81 924 non-turbo

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

I cant see your pics.
The compressor + comes from the low pressure switch which gets its feed from the amplifier. The amplifier is a small black box under the dash by the glovebox that controls the compressor on/off.

The 924 didn't have a factory high pressure switch. It was probably left disconnected for that reason.
The clutch - is grounded at the compressor body.

carrera clone · Joined: 02 Mar 2013 Posts: 8 Location: AUSTRALIA

Hi it's definitely a pressure switch, it could have been disconnected for a reason, does it work, I've retrofitted a few older cars which were originally r12 refrigerant to 134a and found that early pressure switches made the system short cycle as the hi side pressures were slightly higher, they are usually wired in series with the compressor positive wires, as for the earth wire cut on compressor, it's just an extra earthing point, some after market brackets did not earth that well to block
Good luck
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1980 carrera gt clone 931
1993 911 3.6 turbo
1998 boxster s
2004 cayenne turbo
1995 928 gts