Is Vintage Air supposed to function this way?
 

Is Vintage Air supposed to function this way?

Maybe someone can help me confirm my vintage air is working as designed. When I start the truck cold and turn the air conditioning the compressor clutch engages like one would expect. But the Electric fans do not immediately come on. After about a minute the fan will come on and then cycle on and off every minute or so. The air conditioning is working and it gets cold inside. So the function seems to be OK. It would seem to me the Trinary Switch should ground the fan relay as soon as the air-conditioning is activated. I suspect trinary switch turns on the fan when the pressure gets high and then off again when it goes back down. Is this correct function? This all happens before the motor gets warm enough for the ECM to activate the fans. It's a cold start on a day warn enough to need the air immediately upon startup. My fans are not wired like the diagram. The text in the black box in the diagram is the only information Vintage Air provides on the switch function.

I have included some documentation from Vintage Air.
Thanks

Re: Is Vintage Air supposed to function this way?
 

I don't have any experience with Vintage air systems.. You say your fans aren't wired like Vintage air recommends in their diagram?? Maybe that's your problem.. Try wiring them per the diagram and see what happens.

Re: Is Vintage Air supposed to function this way?
 

Yes, it only operates the fan when high-side pressures exceed 254 psi. That's a good way to do it since your fan only runs when it really needs to.

Re: Is Vintage Air supposed to function this way?
 

Do you still have a regular fan? If the electric fan is in addition to ur regular fan (or a secondary electric fan) than yes, do it the Vintage Air way. If it is a single electric fan (not other fans), then I would recommend it kick on by engine temp.

Re: Is Vintage Air supposed to function this way?
 

No engine driven fan is installed. My truck has dual electric fans. They are on relays that activate when the relay is grounded. The ECM grounds them separately at two different temperatures. The air conditioning grounds both the relays when the air system activates the fans. The air conditioning system runs at very elevated pressures if their is no moving air through the condenser. And the pressures are even higher when it's hot out. I don't know of a single factory system that doesn't have some method of moving air through the condenser when the air is on. This is separate from the motor ECM system but either system can activate the fan(s).

I suspect this is operating correctly but wanted another opinion. Currently if you are driving at 40mph there is enough air moving through the system the fans would not activate as the air conditioning system's pressure would never rise enough to activate the high side of the trinary switch.

It's a fairly complicated system. It activates the fan((s) when the pressures are high and will not start the compressor or the fans if the pressures are to low.
Plus one fan activates when the coolant temperature is above 185 deg F and the second one comes on at 195 deg F.

Most of the Vintage Air system is plug and play. If you have electric fans it gets complicated in a hurry. The newer ECM operated the motor fans at a variable speed and the air has to be integrated to the ECM to make it work properly. The only shared connections, between the ECM/ECU and the Vintage air computer are the fans relay grounds on my system.

I have been considering putting the Air-Conditioning Gauges back on to confirm the high side pressures are what I think they are. A Vintage Air system with an engine driven fan doesn't even use the Trinary Switch. It only requires a switch that is for a low cutoff to protect the compressor.
Cheers

Re: Is Vintage Air supposed to function this way?
 

The VA schematic is for a condenser fan, not for your engine cooling fan. Modern cars typically have both since R134 is not all that efficient and pressures will rise when idling in traffic.

Re: Is Vintage Air supposed to function this way?
 

My fans are used for both functions, engine and condenser.
The Corvette, my motor came out of, had this exact set up.