disco111 Posted August 23, 2009 Share Posted August 23, 2009 Hallo everybody I owne a LR 90 2000 td5 with air-co and an electrical problem on it. As an technical/electrical educated enthousiast I bougth an electrical manual and so I started my search to find the fault but on my way in the electrical plans I found the item "trinary switch" between the ECM and the air-co unit. Does anyone know the funtion of it ? Does anyone have some details over the circuit arond this item ? Many greetings from Ghent Belgium Martin. Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted August 23, 2009 Share Posted August 23, 2009 'Tri' meaning 3. So TRIple engined = having three engines. TRIangle, = having three angles. The term Trinary seems to be popular in Air conditioning systems. It means having 3 functions or elements. It becomes a bit clearer if you look at the Circuit Diagram for a 2002 Defender, TD5 with AC. Here it isn't called a trinary switch, but a 'Sensor-Pressure-Air-Conditioning'. Inside the box you will see three pressure switches, High, Medium, and Low. Physically the switch is screwed into the Refrigeration circuit to monitor the pressure. If the pressure goes too high (the circuit is too hot) or the pressure is too low, the circuit is broken, so the compressor clutch is never switched on. Note the connector number of this sensor - C0279. Now go back to the circuit closer to the car you are interested in, 1999 Defender, TD5 with AC, and look for the trinary switch. The connector is also C0279. Looking at the Disco 2 system, Low pressure is 2 - 2.3 bar, High pressure is 26 - 32 bar. Looking at the 38A system, Low pressure is less than 1.2 bar, High Pressure is greater than 30 bar, Medium pressure (when the system will operate) is between 2.4 and 21 bar. HTH Quote Link to comment Share on other sites More sharing options...
disco111 Posted August 24, 2009 Author Share Posted August 24, 2009 Hallo David Sparkes Many thanks for your very clear explanation,I'm gone take a look in the second part of my electrical manual as you told me. Now everything becomes clear to me.Its logical that there is some kind of a pressurecontrol on the cooling circuit. Only the choice of the name"trinary" is a bit strange. Thank you very much and many greetings from Belgium. Quote Link to comment Share on other sites More sharing options...
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