Vintage air wiring

[az1970k5]

I have been having issues with the wiring in my VA kit. I installed an old air unit years ago and had no issues and worked flawless. I had some issues with my VA unit but they resolved and sent me the missing parts. I purchased the complete VA system including the trinary switch so that I could run an electric fan to kick on with the compressor. As I was near my completion I noticed the harness and relay that wires the positive from the circuit breaker to the battery as well as the grounds and the trinary switch wiring was missing the purple wire to run the electric fan. I called VA technical support and they advised me I now needed to order the electric fan wiring kit which was another 60 plus shipping. I went ahead and ordered it on their advise and finished up the entire front end wiring until the electric fan wiring kit came in as I was advised by tech support. I received the fan wiring kit and it is the exact same wiring schematic with the exception of the addition of the purple wire which runs the electric fan. Everything else is identical. If I wire this electric fan wiring kit per the instructions I will have a total of 2 relays and 2 circuit breakers up front and every wire on the trinary switch spliced together. Was I advised wrong? It seems to me it should be one or the other harness, not both. Anyone recently installed a VA kit with the trinary switch and electric fan wiring kit? I just hate calling their tech support.

[Hart_Rod]

Is this the wiring diagram you used?

[cleszkie]

My kit came ready with the fan wiring, and I ordered the trinary switch from the get go. So I have had no problems with my system. I didn't know you could order the kit with a harness that deletes the fan wiring.

[Andy4639]

The trinary wiring harness is different than the regular binary wiring.

The brinary wiring should only have 2 wires in it and the trinary should have 4 wires.

There are 2 styles of pressure switch, binary and trinary.

The binary switch simply splices between the compressor clutch and evaporator thermostat and taps into the high pressure line. When pressures exceed safe limits, the switch opens the circuit to the compressor clutch thus disengaging the compressor until pressure return to normal.

The trinary switch operates much the same as the binary in that it shuts down the compressor when pressures rise. However, the trinary also controls an electric fan on the radiator that pulls additional air across the condenser to bring pressures down.