A/C Compressor Sensor broken

[Lmarche]

Hi,
When reinstalling the A/C compressor after engine mantenience, I hit a sensor with 2 cables installed on a hose coming out of the compressor.
Can someone name the connector-sensor?
I can’t find it to replace it.
Leo.

[walt]

Not sure these were standard equipment on the SC from the factory. Check with Griffiths AC for a replacement. You can also test by just bypassing the switch. I had one go bad and have yet to replace it.

[86 911 Targa]

This may be the connector that senses too low, and too hi pressure in the A/c.

The sensor will shut down the pump.

Is it integrated in the A/C hose, or is it a separate item?

If integrated, you may have to replace the hose.

Gerry

[GH85Carrera]

The factory did not use them at all until the 964 model. It is indeed the pressure sensor for high or low pressure. You will never find it on the Porsche parts list for the car as Porsche never sold it. It is like finding parts for the ABS or power steering for the SC. It does not exist.

Griffiths is a good choice. My system is the Griffith's system and he puts a T fitting in the hose where the sensor can be unscrewed and replaced without losing the refrigerant charge. Take some good photos of the line and the fitting, and we or Charlie Griffith can identify it.

[Peter M]

Leo,
It's a Binary switch that is used to protect the AC components from over pressure situations by disabling the AC compressor drive when the pressure exceeds a certain level. A Trinary switch has extra contacts to protect the compressor from under pressure situations as well where the lack of gas and therefore oil flow can cause the compressor to seize if operated continuously. Binary's have two wires (one set of pressure contacts) and Trinary's have 4 wires (two sets of internal contacts).

You can simply unscrew the switch from the hose fitting using a spanner. The refrigerant won't leak out as there is a schrader installed into the hose fitting to prevent this.

Whilst that isn't a Porsche part, they are common and very easy to get.

There should be a brand and part number somewhere on the switch that you can then use to get a replacement. Alternatively just measure the size and thread pitch of the fitting on the hose fitting and you can buy a suitable replacement from eBay very cheaply as they pretty much generic.

[kuehl]

If you have the same hose you have in the picture (compressor to deck lid condenser) with a binary (low and high side pressure monitoring) air conditioning pressure switch (This is aftermarket: broadly meaning its not an original factory part or design. Aftermarket does not mean inferior or better, simply not original. And, original does not mean better than aftermarket).

To verify: carefully remove the black cap electrical connector from the top of the switch, be careful not to rock it off as their are 2 male contacts in the switch embedded in the black plastic and they can bend and break the plastic). Take an open end wrench and put it on the hex section of the metal portion of the switch (probably something close to 9/16"). Turn counter clockwise enough so you can turn the switch assembly off the fitting on the hose end. Wear safety glasses and a leather glove (many times refrigerant will come out until the needle in the schrader valve seats closed). Measure the inner major diameter of the switch's female threaded hole. A 7/16"-20 thread is approximately .4375" or 11.11 mm, the common size used. Or it could be 3/8"-24 thread, which would be 0.375" or 9.52 mm.

If the internal thread of the switch is 7/16" then you would buy this:
https://www.ebay.com/itm/BINARY-FEMALE-AIR-CONDITIONING-HI-LOW-PRESSURE-CUT-OFF-SWITCH-SP4087-7-16-20-134/311942266650?hash=item48a1353f1a:g:IxoAAOSweuxWRL6 e

Buy 2 (one to put on the ac hose fitting, and one to put in your vehicle glove box or tool box) because somethings manufactured today don't last as long as they did prior to the time when bra's were used for technical support rather than as stone guards.

When you unscrew the switch from the AC hose fitting, look inside the female thread port of the switch. There should be a green bushing seal deep inside. Check your replacement switch to insure it also has this green bushing seal before you screw it on the ac hose fitting.

Take some silicone spray or a light oil and lightly lubricate the OD of the black plastic on the switch. Look at the electrical connector black cap and orientate the 2 female spade terminals buried in it to match up with the 2 male spades on the switch. Does not matter which terminals mate because its a series circuit. Carefully wiggle the black plug back on the switch until it seats down evenly.

Again, safety glasses and leather gloves. Hand tighten switch about 2 lbs max, just enough until you feel firm resistance.

If you have unplug the 2 wires from the system, one wire (female spade) goes to the factory AC power wire connector (funky translucent plastic plug on wire near oil filter and RH tail light assembly), other wire to the compressor clutch. Route the wires so they don't flop around.

Griff
https://griffiths.com/

[GH85Carrera]

^^^^ Yea, what he said!

This is a case where the aftermarket is clearly better than the factory original system designed and sold by Porsche. They had no pressure sensor at all, so it could damage a perfectly good compressor by running with little or no refrigerant. It could also keep running when the pressures are too high and the seals all blow.

Like the front condenser fan came with no fuse whatsoever. More than a few 911s burned to the ground because of the lack of fuse. It is hard to argue it is not better to put a fuse in the power wire for that fan. Porsche was in a bad state in those days. The CEO of Porsche at the time, Ernst Fuhrmann, hated the 911 and wanted it dead and replaced with the 928. He forbid any further R&D on the 911 and as soon as sales of the 911 slowed enough, he could kill it. Fortunately for us an American, Peter Schutz, took over and changed that. He personally saved the 911.

[Lmarche]

All answers had been very helpful, As soon as can I will measure it to look for a replacement.
Lucky me, I have all winter to look for it!
Thanks for your help!

[Lmarche]

Hi,
This is an actual photo of the switch.
One of the male connectors vented when I hit it. Then, I tried to align it to reattach the female connector, and it broke.
I found this online but first I need to mesure it as adviced.
Thanks for all the help.

[blucille]

it looks like you only brooke the connector on the wire, not on the actual switch/sensor. If that's the case, simply crimp on a new connector and go with it. No need to evacuate the system, no need for anything except a new electrical connector.