AC and Fan wiring question

[David_L]

I'm now working on wiring up my AC from Northern Race car. It looks fairly stright forward. Richard says you need to use the Hayden fan control PN3647 that will trigger the fan at temp plus will trigger the fan anytime the AC kicks on.

Wiring this also seems stright forward except I already have the holley sniper and a manual dash switch that will ground trigger the engine fan relay to turn on the fan. I talked to Richard and he seems to think you can only have one or the other, not both. I kind of like having the Sniper and the manual switch control the fan.

I was wondering if you can just join the current RF fan power wire together with the Hayden ORANGE Fan #1 wire then connect that to the fan. That way if there was power from ether source the fan would come on. If this works I wouldn't even need to Hayden temp prob as the Sniper could trigger the normal fan relay.


Also the Sniper has a Orange wire (Ground Triggered AC Relay) on the 10 pin connecter that will increase RPM when the AC kicks on. Where and how is this wired?

[Papa]

David,

I know we've been exchanging PMs on this, but I think it might be helpful to get more eyes on what I sent and see what others think. The Hayden controller is an adjustable temp trigger based on a probe that then triggers the fan on at the selected temp as well as when the AC clutch is on.

Here is way to do the same thing using the Sniper and/or your manual override using a couple of relays:



In this diagram, think of the "Temp Switch" as the Sniper. If you built this controller circuit, you wouldn't use the RF circuit, although I think you could actually consider that entire circuit what is represented by the first relay in the diagram and then you would just need to implement the second relay for the AC clutch trigger to work.

[David_L]

David,

I know we've been exchanging PMs on this, but I think it might be helpful to get more eyes on what I sent and see what others think. The Hayden controller is an adjustable temp trigger based on a probe that then triggers the fan on at the selected temp as well as when the AC clutch is on.

Here is way to do the same thing using the Sniper and/or your manual override using a couple of relays:



In this diagram, think of the "Temp Switch" as the Sniper. If you built this controller circuit, you wouldn't use the RF circuit, although I think you could actually consider that entire circuit what is represented by the first relay in the diagram and then you would just need to implement the second relay for the AC clutch trigger to work.

Thanks much! This might be the solution. Be interested to see what others have done. I do remember one person just flipped the manual switch every time ac was turned on...

[Papa]

I found this on the Holley forum for the AC wiring:

https://forums.holley.com/forum/holl...9632#post99632

[David_L]

I still dont see why my idea of adding adding a 30 amp diode to the Hayden fan power and also to the RF fan power lead then joining the 2 together after the diodes then connecting to fan wouldn't work. This would keep power from flowing back to the relay on the side that was not activated. The ground wire shouldn't matter.

This way the Hayden could turn on the fan when AC was on and I wouldn't even need the Hayden temp probe as the sniper would turn on the fan with the RF relay.

Any drawback to this approach. Of course I'm a beginner at wiring but it seems simpler. Can get 20 30amp diodes on Amazon for $9.

[David_L]

I found this on the Holley forum for the AC wiring:

https://forums.holley.com/forum/holl...9632#post99632

Thanks I saw that as well. I also read that most guys weren't the the rpm boost (10 pin orange wire) and it was working fine. So going to go without and see how it works. The sniper should bust rpms by default anyway.

[Papa]

I still dont see why my idea of adding adding a 30 amp diode to the Hayden fan power and also to the RF fan power lead then joining the 2 together after the diodes then connecting to fan wouldn't work. This would keep power from flowing back to the relay on the side that was not activated. The ground wire shouldn't matter.

This way the Hayden could turn on the fan when AC was on and I wouldn't even need the Hayden temp probe as the sniper would turn on the fan with the RF relay.

Any drawback to this approach. Of course I'm a beginner at wiring but it seems simpler. Can get 20 30amp diodes on Amazon for $9.

The relays in the diagram I posted are diode-protected, so if you don't want to use those particular relays you may want to use diodes in the circuits.



As for using the Hayden stuff for just turning the fan on when the AC is on, it's overkill in my opinion. All you need is a single relay triggered by the AC clutch. Ultimately, it's your build, so do what you feel comfortable with.

Dave

[David_L]

The relays in the diagram I posted are diode-protected, so if you don't want to use those particular relays you may want to use diodes in the circuits.



As for using the Hayden stuff for just turning the fan on when the AC is on, it's overkill in my opinion. All you need is a single relay triggered by the AC clutch. Ultimately, it's your build, so do what you feel comfortable with.

Dave

I agree it's overkill. lol But I already have the Hayden and it's too late to return it so I was just trying to figue out if I could still use it without purchasing more parts. Of course purchasing more parts goes with the hand in hand with these cars!