My super-duper fan controller magic box!

[davepl]

I'm installing an eRod engine, and GM "simplifies" the fan contol by tying the two independent fan control wires together on a single relay. Since I have dual fans, I wanted discrete control. I split the wires out of the fusebox and then built my own 3-relan fan controller.

Why 3 wire?

With HI and LO control, allows you to have these states:

No fans
Both fans at 6V
One fan at 12V
Two fans at 12V

The point being the ideally it spends most of its time running both fans in 6V mode (12V but in series).

Here's the inside and outside of the project box. If anyone wants to duplicate it, it's basically the stock wiring setup that came in the older F-bodies, so there schematic is out there for that.

[Mrturner1]

Nice! I have dual 12" electric fans and right now and they are wired as per the instructions, but I've been thinking about some kind of single/dual controls. Adding the 6v and 12v option is a pretty cool idea.

Adding a relay would be nice too, and safer. Mine are Flexalite fans and they are wired to a small black box that has the temp control knob, but I don't think there's a relay in there. I'd have to open the box to be sure though

[donandal]

I have an E-rod package also, but have not started the wiring yet. I do know it does have just the single wire out put to a single fan. I also have dual fans.

So you have my attention.

I don't know much about wiring so here come the dumb questions.

how does two fans is series end up at 6V?
is that lower voltage better for motor longevity?

what are the trigger signals? Air cond. and water temp? something else?
I have a trinary switch with my A/C, does that do the same thing?

that does look very professional....

[wbc409]

It has to do with basic electrical theory. For Voltage in series, your voltage drops across each load. Every item or load in a series circuit will see the same amperage. running identical loads you have the same voltage drop across each load. If you have different loads then the voltage drop across the different loads will not be equal. In a 12 volt series circuit you will "drop" the full 12 volts across series circuit. There could be 2 loads, or 12 on the series circuit. You can't magically add or subtract voltage or current from the circuit.
On a parallel circuit, (like the circuits in your house) the voltage stays the same but the amperage drops. With the relay setup he is using, it is a combination, series - parallel circuit.

[donandal]

So does that make the motors last longer, or just run slower so they sound quieter?

Also, my instructions say that the fan needs to be hooked directly to the wire provided ( not thru a relay ) in order for the computer to sense that load. Would this setup still indicate that load to the computer?

Thanks

[wbc409]

The fans won't be spinning as fast, so they should be quieter. It gives you more precise control over your cooling fans so they should hopefully last longer. Whether or not it works with that controller, davepl will have to answer that because I don't have any experience with the controller.

[davepl]

This won't work if you're following the eRod instructions, which you should do unless you're adventurous. I make no claims this will work, I only hope it will :-) To make use of it I have to also reprogram the computer to redefine the 7 fan states and the dozen or so fan state transitions, as the fan tables are now pretty complicated. But I have a rough idea what I'm doing. If you do not change the computer's programming then it turns on both wires at the same time anyway so just physically splitting out the wires without reprogramming buys you nothing.

The schematic will help the curious. Basically in the lowest setting, with only the LO fan active, both fans run but in series, so they split the current and should run at half speed, quieter than one fan at full blast.

I forget where I found this circuit, but it says it's the same as the F body fan circuit, and I think some Mazdas use a similar setup.

Here's a bit of info on where I'm at with the programming side (clearly I'm pretty new, as you'll see):
http://www.hptuners.com/forum/showth...027#post428027

[donandal]

thanks!

What I need is a super-duper wiring guru...

Someone local who wants to help a complete moron do his wiring.
I'm sure I'll get thru it.

[Longhornss]

Originally Posted by davepl

This won't work if you're following the eRod instructions, which you should do unless you're adventurous. I make no claims this will work, I only hope it will :-) To make use of it I have to also reprogram the computer to redefine the 7 fan states and the dozen or so fan state transitions, as the fan tables are now pretty complicated. But I have a rough idea what I'm doing. If you do not change the computer's programming then it turns on both wires at the same time anyway so just physically splitting out the wires without reprogramming buys you nothing.

The schematic will help the curious. Basically in the lowest setting, with only the LO fan active, both fans run but in series, so they split the current and should run at half speed, quieter than one fan at full blast.

I forget where I found this circuit, but it says it's the same as the F body fan circuit, and I think some Mazdas use a similar setup.

Here's a bit of info on where I'm at with the programming side (clearly I'm pretty new, as you'll see):
http://www.hptuners.com/forum/showth...027#post428027

I have the same engine and controller in two, soon to be 3 project vehicles at the shop. My plan is to pull the wiring apart at the relays and use the fan logic from 2010 camaro to run both fans, having them both come on full at their respective temperatures.

I am curious to know what you are using for fans, there is something about that primary fan wiring that is throwing me off. Where is this fan getting its ground at low speed.

[davepl]

In low speed mode Fan 1 grounds itself to Fan 2. That means

GND - FAN1 - FAN2 - PWR

So both fans, when only the LO relay is energized, are connected in series and run at 6V splitting the voltage.

When both relays are energized the fans each have their own path to ground and their own power supply, so they both run at 12V.

Does that help? I'm using dual Spal 12V fans.

[Longhornss]

Originally Posted by davepl

In low speed mode Fan 1 grounds itself to Fan 2. That means

GND - FAN1 - FAN2 - PWR

So both fans, when only the LO relay is energized, are connected in series and run at 6V splitting the voltage.

When both relays are energized the fans each have their own path to ground and their own power supply, so they both run at 12V.

Does that help? I'm using dual Spal 12V fans.

Ok, I saw that, it was wired into the second fan and thought that was what was going on here.
I am used to having a 3 wire fan for dual speed control, but I suppose that is still a 12V system.

I guess I will need to bush up on some electrical theory and do a bench test on this setup. This may be another option for the projects around here, thanks for the idea.

I always use Spal fans great product.

[Ruscal]

I am also looking at an E Rod engine, and wondered whether to use the GM built in fan control or use my Derale PWM that is currently controlling the twin Spals on my SBC. The Derale is working well to cool the engine and keeps the fans as quiet as possible. A 430 HP motor will need more cooling, so noise may go up a bit. I have only been using the Derale for a couple of months, so don't know about reliability. The unit cost about $160.00 ish. It also has a tap for AC integration.
Russ

[davepl]

Originally Posted by Longhornss

I guess I will need to bush up on some electrical theory and do a bench test on this setup. This may be another option for the projects around here, thanks for the idea.

I bench tested it with headlights, worked great. Haven't tried it with the actual fans yet though!

[Longhornss]

Originally Posted by Ruscal

I am also looking at an E Rod engine, and wondered whether to use the GM built in fan control or use my Derale PWM that is currently controlling the twin Spals on my SBC. The Derale is working well to cool the engine and keeps the fans as quiet as possible. A 430 HP motor will need more cooling, so noise may go up a bit. I have only been using the Derale for a couple of months, so don't know about reliability. The unit cost about $160.00 ish. It also has a tap for AC integration.
Russ

The only thing I would consider here is that the e-Rod is set up to turn the fans on at optimal temperature to control the emissions, you being in Cali I am sure this is a big issue. I believe the fan Relay(s) are triggered to come on in the E-Rod at 200-210*.

[davepl]

Originally Posted by Longhornss

The only thing I would consider here is that the e-Rod is set up to turn the fans on at optimal temperature to control the emissions, you being in Cali I am sure this is a big issue. I believe the fan Relay(s) are triggered to come on in the E-Rod at 200-210*.

A good point and a valid concern, but I plan to keep it running at the same temps as stock, just to have a quieter "strategy" in the computer for keeping it there.

Stock computer calibration turns on all fans at 206.6F. I'll likely have it do low speed at 200 and high speed at 210, something like that, to keep it in the same general temp range.

I don't have to pass emissions where I'm at (WA), but I'd still like to keep it clean. That's why I'm running all 4 cats and so on.

[Longhornss]

That comment was more intended for Ruscal for what he was asking about his controller.

However have you considered going to the Tune reposetory from HP Tuners and pulling a 2010 Camaro Fan Strategy. I have looked at them and they appear to stagger the fans like you are talking about and follow the 7 conditional command procedures. 1 fan at set temp, then both fans at higher temp and them back down to one, then both off.

[davepl]

I'll take a look at the tune, thanks! I'm worried they might use PWM which would cause my relays to just buzz, since they're not solid state. But if they just do on/off it's probably a great example to look at!

[Longhornss]

Originally Posted by davepl

I'll take a look at the tune, thanks! I'm worried they might use PWM which would cause my relays to just buzz, since they're not solid state. But if they just do on/off it's probably a great example to look at!

No, I have already looked at this they are Dual Discrete fans, Just like the E-Rod ECM. Should be exactly what you are looking for. I know emisions are not an issue for you but if it were for someone else, Like the 96 Impala I am doing an install in it is. So using the Camaro logic should keep the engine temperature happy for the emissions.

only thing I have to try, is see is how adding a A/C ground trigger effects the system. Someone said that feeding a ground into the relay center from a trinary switch, that was not outputted by the computer may cause a MIL Light situation. The suggested fix was to add a small diode to the Green and Blue wires so that signal would not feed back to the ECM.

[davepl]

I'm curious to see what happens if/when I use my "override" switches that will ground the fan triggers. It will trigger the fan relay, that much I don't doubt, but I wonder if that will case a MIL because it no longer sees 12V potential on the trigger lines. I'm told it monitors that, so it might be a problem. If it's temporary (clears when I turn the switch off) I'm fine with that.

[donandal]

Originally Posted by Longhornss

No, I have already looked at this they are Dual Discrete fans, Just like the E-Rod ECM. Should be exactly what you are looking for. I know emisions are not an issue for you but if it were for someone else, Like the 96 Impala I am doing an install in it is. So using the Camaro logic should keep the engine temperature happy for the emissions.

only thing I have to try, is see is how adding a A/C ground trigger effects the system. Someone said that feeding a ground into the relay center from a trinary switch, that was not outputted by the computer may cause a MIL Light situation. The suggested fix was to add a small diode to the Green and Blue wires so that signal would not feed back to the ECM.

You gentlemen know way more about this than I do. Still, I'd like to run this by you. I am planning on running one fan from the ECM as it came wired. I plan on running the other independently thru a selectable temp sensor in the coolant ( vintage air suggested the drain petcock ) set slightly hotter and a trinary switch. With the factory thermostat, wouldn't that keep the temp at the proper value?

[Ruscal]

Originally Posted by Longhornss

The only thing I would consider here is that the e-Rod is set up to turn the fans on at optimal temperature to control the emissions, you being in Cali I am sure this is a big issue. I believe the fan Relay(s) are triggered to come on in the E-Rod at 200-210*.

luckily the '67 is smog exempt in California. I just would like the truck less smelly, therefore the E rod. The Derale PWM has a multi-turn pot to set the temperature threshold. I have it set at 195F and run a 180 T stat. It is working good. The temp sender is inline at the lower rad hose per Derale instructions. (not where you would think it should be....) With the LS motor, just dial up the temp to 205. More MPG would be another benefit over the SBC, but the payback would take awhile!
Russ

[Longhornss]

Originally Posted by donandal

You gentlemen know way more about this than I do. Still, I'd like to run this by you. I am planning on running one fan from the ECM as it came wired. I plan on running the other independently thru a selectable temp sensor in the coolant ( vintage air suggested the drain petcock ) set slightly hotter and a trinary switch. With the factory thermostat, wouldn't that keep the temp at the proper value?

Sounds like you have it figured out.

Another option for fan controls is the Dakota Digital unit... You can use the Coolant temp sensor location in the passenger side head to install sender. Then use it to trigger the fans at any given temp and have them turn off at any given temp if you don't want or don't have access to changing the ECM and factory wiring. You can also wire in the a/c trigger directly.

[Longhornss]

Originally Posted by davepl

I'm curious to see what happens if/when I use my "override" switches that will ground the fan triggers. It will trigger the fan relay, that much I don't doubt, but I wonder if that will case a MIL because it no longer sees 12V potential on the trigger lines. I'm told it monitors that, so it might be a problem. If it's temporary (clears when I turn the switch off) I'm fine with that.

That would be where the diode comes into play. Installed into the blue and green triggers from the ECM. The ECM would be un aware of the added ground.
I of course I am curious to know how this works without them though. Again at this point this is all theory I do not know how the MIL will be affected if at all.

[Andy4639]

I have been looking at several mods for my 6.0 LS.
I wanted something that will cut the fans off once the truck is up to speed on the road to keep the fans from running for no reason. At speed the fans are worthless and it just burns the motors up faster.

Right now mine is setup like this:
#1 no ac on fans are both triggered by the PCM to come on @ 185* water temp. They cut off anything under 185*
#2 -One fan will come on with the AC compressor. (DS)
The other one (PS) want come on unless the water temp gets to 185*.

I have them all running off relays that are triggered by the grounds.
So far I haven't gotten any codes set by this setup. But I haven't drove it but one time and the fans never came on because of the water temp was 179*.


Vintage air make a Trianry switch that is put in line with the AC to run the fans at AC pressures. It will cut the fans off at speed if there is enough temp drop on the coils to keep the condenser happy. I like this setup but don't want to take my AC a part to install it. If I have to ever take it down though I will add this feature.



Painless makes a system also. You can program this one with the VSS signal to cut off at any given speed. The biggest draw back I see is the box being mounted.



Electric cooling fans have become a mainstay when it comes to keeping any type of vehicle’s engine cool. This state-of-the-art fan control system includes an under hood rated solid state pulse width modulation controller, 12x1.5MM threaded temperature sensor that threads directly into the extra port on the passenger side head of any LS engine, large gauge fan wires and a labeled vehicle integration wire harness, mounting hardware and 70 Amp fuse and connectors. The F5 Dual Fan Controller is rated to control two 35 Amp cooling fans. Controller features include dual cooling fan control from 50% up to 100%; A/C compressor override that runs the fans at 100% duty cycle if air conditioning is kicked on. Kit also includes a three position toggle switch that gives you manual control of the cooling fans; position one is 100% fan on, position two is normal operation and position three is 0% fan or fan off. Also included is a push button switch which is used to set the vehicle speed at which you like the cooling fans to shut off above. See illustrated installation manual for more information.

The Dakota system I haven't gotten that far into it yet to like are dis like it. Need to do some more reading. What I read the other day was it's able to turn the fans off at speed but want turn them back on without turning power off to the controller. I'm not sure about that.

[Hart_Rod]

Originally Posted by Andy4639

I have been looking at several mods for my 6.0 LS.
I wanted something that will cut the fans off once the truck is up to speed on the road to keep the fans from running for no reason. At speed the fans are worthless and it just burns the motors up faster.

Right now mine is setup like this:
#1 no ac on fans are both triggered by the PCM to come on @ 185* water temp. They cut off anything under 185*
#2 -One fan will come on with the AC compressor. (DS)
The other one (PS) want come on unless the water temp gets to 185*.

I have them all running off relays that are triggered by the grounds.
So far I haven't gotten any codes set by this setup. But I haven't drove it but one time and the fans never came on because of the water temp was 179*.


Vintage air make a Trianry switch that is put in line with the AC to run the fans at AC pressures. It will cut the fans off at speed if there is enough temp drop on the coils to keep the condenser happy. I like this setup but don't want to take my AC a part to install it. If I have to ever take it down though I will add this feature.



Painless makes a system also. You can program this one with the VSS signal to cut off at any given speed. The biggest draw back I see is the box being mounted.



Electric cooling fans have become a mainstay when it comes to keeping any type of vehicle’s engine cool. This state-of-the-art fan control system includes an under hood rated solid state pulse width modulation controller, 12x1.5MM threaded temperature sensor that threads directly into the extra port on the passenger side head of any LS engine, large gauge fan wires and a labeled vehicle integration wire harness, mounting hardware and 70 Amp fuse and connectors. The F5 Dual Fan Controller is rated to control two 35 Amp cooling fans. Controller features include dual cooling fan control from 50% up to 100%; A/C compressor override that runs the fans at 100% duty cycle if air conditioning is kicked on. Kit also includes a three position toggle switch that gives you manual control of the cooling fans; position one is 100% fan on, position two is normal operation and position three is 0% fan or fan off. Also included is a push button switch which is used to set the vehicle speed at which you like the cooling fans to shut off above. See illustrated installation manual for more information.

The Dakota system I haven't gotten that far into it yet to like are dis like it. Need to do some more reading. What I read the other day was it's able to turn the fans off at speed but want turn them back on without turning power off to the controller. I'm not sure about that.

Andy - I'm pretty sure you can shut the fans off at certain speed from within the tune.