Trinary Switch Integration with Dual Fans

[Chvy2NV]

subd... im not ready to do this yet but thanks for the info.. Im lost with all this..

[trobert3]

Originally Posted by 87chevy.com

Otjer option you simply install the factory high side pressure sensor and wire the 3 wires to ecu and no need for resistors or anything... then operates like factory

I have a 08 express van e38 computer and engine stand alone harness, I would like to know which 3 wires from ECU goes to the high pressure switch?
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[ls1nova71]

Originally Posted by trobert3

I have a 08 express van e38 computer and engine stand alone harness, I would like to know which 3 wires from ECU goes to the high pressure switch?
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X1 pins 12, 13 and 34.

[trobert3]

Originally Posted by ls1nova71

X1 pins 12, 13 and 34.

Ok, Thanks for the reply, any order that they need to be wired to the sensor .
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[ls1nova71]

Originally Posted by trobert3

Ok, Thanks for the reply, any order that they need to be wired to the sensor .
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The sensor plug is numbered 1-3, pin 1 tan wire goes to pin 13 on the ECM, pin 2 gray wire goes to pin 34 and pin 3 orange/black wire goes to pin 12.

[trobert3]

Originally Posted by ls1nova71

The sensor plug is numbered 1-3, pin 1 tan wire goes to pin 13 on the ECM, pin 2 gray wire goes to pin 34 and pin 3 orange/black wire goes to pin 12.

Thank you LS1nova.
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[trobert3]

[QUOTE=trobert3;8924709]Thank you LS1nova.

[trobert3]

Found wires and plugged them into sensor, still no fans with ac turned on. System is not fully charged could that be the reason or does it have something to do with the Tuner?
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[Rich84]

Fully charge the system. If I recall correctly the compressor has to be on for the fan to run. It's been a while though.

[dayj1]

Originally Posted by trobert3

Found wires and plugged them into sensor, still no fans with ac turned on. System is not fully charged could that be the reason or does it have something to do with the Tuner?
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Rich84 is right, the AC system needs to be charged. But, if you're expecting the fans to come on when you turn the AC on, it doesn't work that way. The fans come on as needed based on pressure in the AC system.

With that being said, I thought I read where you had an '08 ECM (Gen IV). I don't believe you will be able to get the fans working with just the pressure transducer. You're going to need a way to get a message on the CAN bus to let the ECM know that AC is being requested (the pressure transducer alone worked for a few select Gen III OS variants) but not Gen IV. Of course this type of thing is subject to change as HP Tuners and other tuning software advances and adds patches over time.

[nsb29]

My motor is out of a 09 G8 it uses a pressure switch and a brinary switch. The fans are wired using three relays, When I turn the a/c on I have low speed fans almost right a way. high speed comes on in stop and go traffic and no fans on the highway but like previously stated your system Must be completely charged

[trobert3]

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[trobert3]

Thanks for the input everyone, I’m still looking for a way to make this work.
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[First c10]

I have an 08 gen 4 and the only way to get the ac to work like stock is to get the info on the canbus system. With aftermarket ac setup(old air products) I used the 3 relay set up with 2 fans highspeed and lowspeed. I connected my high speed fan wire (can’t remember the color) from my pcm to the relay and tied the trinary switch into it also. No problems with pcm checks and when I turn ac on and the pressure gets to it’s closed contact setting on the trinary switch one fan comes on full speed. When my water temp gets to my low speed setting it turns on the other fan to high speed. But when ac is off my system operates normally low speed high speed. Hopefully it makes sense.

[trobert3]

Thanks for the info First c10, by chance are you able to draw a diagram of how you did the wiring. I’m not good a wiring again thanks!
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[First c10]

Originally Posted by trobert3

Thanks for the info First c10, by chance are you able to draw a diagram of how you did the wiring. I’m not good a wiring again thanks!
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I am out of town till next weekend. I will look for my schematic I made when I get back.

[trobert3]

Ok , Thanks
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[nsb29]

if your using a pressure transducer you run a brinary switch not a trinary this could be your problem I made that mistake and nothing worked