GMPP Harness with Vintage Air and Dual Electric Fans??

[dhutton]

That’s because if you want fan activation you need a trinary switch. The binary switch will only kill the compressor with damaging pressures situations.

You can simply turn on your fan when the compressor is running rather than using pressure and the trinary switch. Fans will run more often but it will work. Many folks do it this way....

Don

[parsonsj]

Many folks do it this way....

I'd go so far as to allow that most folks do it this way. I think that's the recommended way for wiring a binary switch: compressor on means fan on.

[badazz81z28]

I'd go so far as to allow that most folks do it this way. I think that's the recommended way for wiring a binary switch: compressor on means fan on.

Most folks? The binary switch is a kill (safety) switch for the compressor, not an activation? Are you suggesting just going to a manual fan "on-off" switch and manually turn the fans on when the AC is on? Why would you not want the automatic feature with a trinary?

[dhutton]

Most folks? The binary switch is a kill (safety) switch for the compressor, not an activation? Are you suggesting just going to a manual fan "on-off" switch and manually turn the fans on when the AC is on? Why would you not want the automatic feature with a trinary?

You can make it automatic without a trinary switch. Compressor on, fan on. Compressor off, fan off. It it simple and effective. No manual switching needed.

[parsonsj]

You can make it automatic without a trinary switch. Compressor on, fan on. Compressor off, fan off. It it simple and effective. No manual switching needed.

Yes, exactly.

[Vintage Air tech.]

Its true, You can have the fan(s) engage when the compressor is kicked on. But by utilizing the fan circuit function of the trinary switch, the fans will only engage when the high side pressure reaches 254 psi then disengages at 175 psi.
with this method along with a cooling mgmt. system it will will ensure your fans are being engaged only when needed. This is the most efficient method.
https://www.vintageair.com/instructions_pdf/909952.pdf

[parsonsj]

Well... the most efficient method is to use an ECU along with a high side pressure sensor and a pwm controller. But I digress...

Anyway, yes, the trinary setup is more efficient than the binary setup.

[rcarson25]

So, I am coming in late to the game here but I have some questions based on what I am reading literally all over the boards. I drew up this highly professional wire diagram using my daughters scented colored pens and wanted to see if people who know what they are doing agree that I am on the right track. I want to keep this clean so I am looking to add fuses and relays to the goo fuse block. Does this look like it will work well, do I need to wire the trinity differently? I wasn’t sure if i should connect it to a different wire from the ecm or the way I have it in the diagram. Knowledgeable input appreciated.

[dhutton]

Here’s a better schematic of the fan control part. You could add a small relay to pull the green wire low when the compressor is on.

Don

[rcarson25]

I would say that is slightly cleaner haha. Thanks for this, does my trinary switch look right or should that be done differently?

[dhutton]

Or use a trinary switch instead of the small relay.

[dhutton]

I would say that is slightly cleaner haha. Thanks for this, does my trinary switch look right or should that be done differently?

Your trinary looks ok but it’s up to you to verify the correct pins. Connect it to the green wire in the schematic I posted.

Don

[rcarson25]

Just to make sure I am clear here, this diagram is the same as mine, except that fan 2 would be your primary/low speed fan and fan 1 would be your secondary/high speed fan in your diagram. Is that correct? Sorry for my ignorance here, it has been awhile since I have done fan wiring and I don't want to screw this up. Thanks again for the help.

[dhutton]

Just to make sure I am clear here, this diagram is the same as mine, except that fan 2 would be your primary/low speed fan and fan 1 would be your secondary/high speed fan in your diagram. Is that correct? Sorry for my ignorance here, it has been awhile since I have done fan wiring and I don't want to screw this up. Thanks again for the help.

The schematic I posted runs both fans in hi and low mode. They are connected in series for low speed which means 6 volts on each fan. They are in parallel in high speed mode so 12 volts on each fan.

I didn’t try to decipher your relay wiring...

Don

[rcarson25]

Sounds good I was not thinking of this setup running in series more of fan 1 on at low and fan 1 and 2 on for high. This makes more sense to me now.