Correct Trinary Pressure Sensor/Switch
 

Red Dot P/N 71R7500, GM 35899

Open below 2.81 kg/39.9020

Open above 22.8 kg/323.7600

Fan on 8.4 kg/119.2800

Thanks.

One does have to do some crafting to get that integrated?

Physical entry into the high side and clearly some wiring time to keep fan(s) on post shutdown and kill compressor if outside operation limits. Former is my concern. Latter just takes time to configure - my take/comfort level.

Main thing I like is that high side over 325 means something ain't right.

2 times 120F = 240 + 50 = 290 psi. Rule of thumb, right? That gives an extra 35 psi before shutdown if idling in the sun on a hot day in Phonix.

Set aside theories and arguments. This makes sense. If your system is working fine, not needed. If not, then this protects your system/investment.

Good info and great timing for me as I need to get new hoses made.
I guess I need to add a "T" connector for the trinary switch.

Keuhl, what switch do you use in your kits?

How plug and play are these? I have a binary but want to switch to a trinary to manage my ZIMS fan.

Addresses integration:

Binary Switch w/ R-134a Discharge Port 7/16" - A/C Pressure Switch

Discard the binary pressure switch. Integrating adapter goes right on the side of the compressor and clutch wire is close by. Just splice the pressure switch' compressor control in series with the clutch wire.

Yes, need some beef.

It has got to be as onerous as installing a 6AL under the driver's seat.

Directly, same male connection, 4 wires out vs 2.

Then the fans are controlled via a hot all the time feed from the trinary?

Edit - Oops - timing overlap.

Well, you can...

Inline Switch Port - A/C Pressure Switch

Or...

Binary Switch w/ R-134a Discharge Port 7/16" - A/C Pressure Switch


Or just replace your binary switch with the trinary one..

Since Porsche uses a 20 minute time delay so the fan(s) will not run after that time period you might want to consider using a TDR, Time Delay Relay. The only downside to not having a limit on run time would be a dead battery, but only in case the trinary switch fan control section fails "closed".

But my Zims has its own power source and relay and I only have one wire coming to the compressor. Its basically a low voltage trigger wire. So unlike a traditional SPAL fan I would need three wires and not four. Right now i have this wired into the Binary but not sure that is optimal as it takes voltage from the clutch.