Electric Fan Temps

Doppleganger · Apr 2, 2024

Do you guys run one constantly or always on a on-off sensor? Looks like the standard on/off sensor is 185/175. I would think it'd run about that regardless. Dunno.

I'll be running dual fans with one either coming on with AC or manual over-ride when in stop-go traffic.

RanchWelder · Apr 2, 2024

In my opinion, one should come on with water temps and the second with A/C demand, as required.
When I ripped the A/C from my Honda, the secondary fan was not required for cooling.
It never overheated, once A/C was removed.

That said, the GM system runs cooler-ish as a stock feature.
If you run the primary fan off the sensor and the secondary off a switch, you'll be good to go?
Towing or high demand, you'll just have to watch the thermostat and hit the auxiliary fan when required?

That is what I would do. If you can set another sensor to warn you when added cooling could be useful, you would know when to flip the switch manually.
Blinking yellow light?

Doppleganger · Apr 2, 2024

RanchWelder said:
In my opinion, one should come on with water temps and the second with A/C demand, as required.
When I ripped the A/C from my Honda, the secondary fan was not required for cooling.
It never overheated, once A/C was removed.

That said, the GM system runs cooler-ish as a stock feature.
If you run the primary fan off the sensor and the secondary off a switch, you'll be good to go?
Towing or high demand, you'll just have to watch the thermostat and hit the auxiliary fan when required?

That is what I would do. If you can set another sensor to warn you when added cooling could be useful, you would know when to flip the switch manually.
Blinking yellow light?

Great ideas - some along with what I thought it should be but wasn't sure. Thanks very much!

Ricko1966 · Apr 2, 2024

Doppleganger said:
Great ideas - some along with what I thought it should be but wasn't sure. Thanks very much!

Many cars are setup with 1 fan temperature control and a second a trigger off of AC compressor. You can easily run 1 fan off of a temperature switch,trigger a relay off the AC compressor for fan #2. Temp controlled fan dies in traffic,turn on the defrosters,that will trigger your second fan. And turning on the AC in the summer will Immediately turn on 1 fan for better condenser efficiency.

squaredeal91 · Apr 2, 2024

I swapped to electric fans in the 99 vortec 350. I have it on an on off ground switch to my relay. On at 200 off at 185. Problem is the switches I've been getting don't last. There cheap crap. I'm soon going with a fan switch from a 96-99 454. I'm hoping that will lasting quality. I'm still working out details how to force it on with a/c on. Summer is fast approaching lol

Doppleganger · Apr 2, 2024

What on-off temps do you fellas prefer? I'm trying to get wiring and such sorted on my motor but haven't bought a fan sensor yet. There's a spot in both heads - driver's side is getting the temp gauge sensor and the pass side is getting the fan sensor.

Will probably put a manual override on both.

squaredeal91 · Apr 2, 2024

On off Temps depends on engine and thermostat i guess?. I didn't look for a port for the sensor but I think there is one or 2 on the heads. I'll probably use one of the head locations fir the GM switch this time because it would be more accurate
I drilled and tapped my thermostat housing for my current sensor.

hoagster · Apr 2, 2024

Griffin uses a water temp sensor to control the fans, Fan 1 comes on at 185, fan 2 at 210. I'm using my PCM to control the fans and have a water temp sensor if you want it. you'll just have to mkae a relay setup!

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hoagster · Apr 2, 2024

pm me and I'll send you what I didn't use from the kit! including the wiring diagram.

TotalyHucked · Apr 2, 2024

My tuner set mine to come on at 185 and 205, both are temp triggered. Not sure how we'll tackle it when I do the AC since my harness doesn't have an AC circuit (wish I'd known what I know now, would've bought a different harness)

Bextreme04 · Apr 2, 2024

TotalyHucked said:
My tuner set mine to come on at 185 and 205, both are temp triggered. Not sure how we'll tackle it when I do the AC since my harness doesn't have an AC circuit (wish I'd known what I know now, would've bought a different harness)

F-body three wire sensor and wire it right to the PCM. Shouldn't be too big of a deal to run them along the current harness. I got the sensor, stock connector, and wire run all the way to the red/blue connector from a V6 99 F-body in my local junkyard for like $5. If your tuner is using HP tuners or EFI live, they can turn on the AC controls with no issues. It's a bit trickier using the free software and you need to use an F-body 2156 OS as the base operating system for it to work right.

Doppleganger · Apr 2, 2024

I'm running the ProFlo 4 setup so there may be a sensor for the ECU to activate fans - I have enough schematics to sort without delving into that mess yet, so dunno. My Edelbrock heads each have a spot for a temp sensor (2) plus there is another port next to the thermostat if need be.

I'm a couple-three months from getting to this point - just trying to get wiring configurations sorted and semi-installed while there is no cab or front clip in the way.

SquareRoot · Apr 2, 2024

Doppleganger said:
I'm running the ProFlo 4 setup so there may be a sensor for the ECU to activate fans - I have enough schematics to sort without delving into that mess yet, so dunno. My Edelbrock heads each have a spot for a temp sensor (2) plus there is another port next to the thermostat if need be.

I'm a couple-three months from getting to this point - just trying to get wiring configurations sorted and semi-installed while there is no cab or front clip in the way.

Then you'll see this. Remember the on temp is 15 degrees higher than the off temp. Running a fan lower than the thermostat opening is useless (except for ac override). I want my engine at minimum 195 for emissions and drivability (closed loop on the efi). My primary is set at 205, secondary at 215. The AC kick from the PF4 kicks both fans on. I also have direct manual override switches for both that will never get used. If the ECU goes bad, the fans won't matter. You wont need any switches or senders. The coolant temp sensor for the PF4 is the input via the ECU. The PF4 outputs a ground trigger, so you will need relay(s) for the fan(s). BTW, the temp sending unit will read 10 degrees hotter if mounted in the head versus the intake. That aluminum air gap manifold is very good at shedding heat.

CalSgt · Apr 2, 2024

Mine is untested and I haven’t adjusted for temp but I went with a PWM controller from Derale. It will run both fans however fast they need to maintain the temp you set it for. It also spools them up to 60%+ when the A/C is on regardless of temperature.

SquareRoot · Apr 2, 2024

TotalyHucked said:
My tuner set mine to come on at 185 and 205, both are temp triggered. Not sure how we'll tackle it when I do the AC since my harness doesn't have an AC circuit (wish I'd known what I know now, would've bought a different harness)

That's an easy fix. Just tap off the pressure switch that controls the compressor. That's your input via relay to operate the fans. What thermostat you using?

Electric Fan Temps

Doppleganger

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RanchWelder

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Doppleganger

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Ricko1966

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squaredeal91

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squaredeal91

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hoagster

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Bextreme04

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