Auto Cool PWM Fan Controller

Carl Smith

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I have the Auto Cool 85 on its way and will do some installation pics and a video showing it in action. It will power a stock LS electric fan for my 2000 V8 sport. Will update the thread soon.



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I wonder how this will work out, since the LS fan already has a built in PWM controller?
 
I wonder how this will work out, since the LS fan already has a built in PWM controller?

The controller controls the fan ground & monitors temps on the radiator outflow to engine instead. I'm expecting to connect the small green remote on wire wire to the main power to make the fan operate like any other, but the controller managing rpm on its own through ground. I may later opt for a dual fan or lower amp 16 inch fan, but gonna test this out 1st
 
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The controller controls the fan ground ...

My concern is that the startup delay of the built in PWM controller will be a problem. I guess you'll have to test it and see. All you really needed was something the generate a PWM signal in the correct frequency range to the existing PWM controller in the stock fan motor, via the control wire.
Hopefully, my concern is unfounded.
 
My concern is that the startup delay of the built in PWM controller will be a problem. I guess you'll have to test it and see. All you really needed was something the generate a PWM signal in the correct frequency range to the existing PWM controller in the stock fan motor, via the control wire.
Hopefully, my concern is unfounded.

If so then will grab a flex-a-lite fan as well. May anyway just to lower amp load.
 
Yeah, I do not expect the Gen 2 LS fan and a PWM power controller like the autocool to work well together.

Might work just fine.

Pretty good chance this will destroy the fan motor. It's not just a dumb motor like most fans.

The LS fan has a built-in soft start and, I believe, self check which will probably not respond well to the ground switching.

You can look at my threads for a rather more direct way to make this work. :D
 
Thanks for the info guys. Looks like an aftermarket fan may be in order.
 
Decided to just order a 16'' fan, cut out the center webbing from the original shroud, and mount it in the center. If not for the items that bolt to the shroud and having to mock up brackets for those, I would have grabbed an aluminum low profile shroud. Controller came today and had super fast shipping. Waiting on the fan.

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Took the lower rad hose out and installed the 1.50' sensor pipe adapter that came with the kit. The sensor wire bolts on and then need to be individually taped and secured. Bridge FAN A & FAN B together if using one fan and connect the fan ground to FAN A post as well. Middle ground post is main chassis ground.

Located, IMO, the best location for the fan controller. I don't want a $180 piece of electrical equipment exposed under the hood. Routing the 10 gauge fan ground and positive along the passenger side taping into the starter wire for power and the ground entering through a rubber knockout just under the PCM connections. Taking the glove box assembly out to gain better access, along with pulling the carpeting and sound dampening foam at the PCM will give you access to this rubber knockout that has a bundle of wires feeding through. They are just enough space on the side to route the fan ground, sensor, battery, & ignition turn on wires.

Add one for AC on as well if wanted. I taped the 10 gauge wire and other wires to a 10 inch long piece of coat rack so it can be punctured through the rubber and then pulled through from under the hood area once the PCM connections had been removed to gain room. Red wire shown as ground, but will replace with black when it comes and pull back through using this wire. The controller fits well inside the small space in the passenger dash corner. Easy adjustments or wiring mods can be done by popping off the plastic cover. I will still need to mock up a bracket but a ground stud is already inches from the controller as well.

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You need to put a fuse between the starter B terminal and the 10 awg wire! The fuse protecting the heavier starter wire will not protect that smaller wire. Close to the PCM wouldn't be my first choice for that controller, but I guess the options are limited.
 
You need to put a fuse between the starter B terminal and the 10 awg wire! The fuse protecting the heavier starter wire will not protect that smaller wire. Close to the PCM wouldn't be my first choice for that controller, but I guess the options are limited.

Yes, I forgot to mention the inline fuses. They will go on both ground and positive along with the battery + ignition wires to the controller. This is feet from the PCM which is near the floor. The large wire going in is only the ground and just two smaller 12v wires with no huge load.

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Fuse on the ground? Seems like a bad idea to increase resistance (therefore voltage drop) to ground.
 
Took the lower rad hose out and installed the 1.50' sensor pipe adapter that came with the kit. The sensor wire bolts on and then need to be individually taped and secured. Bridge FAN A & FAN B together if using one fan and connect the fan ground to FAN A post as well. Middle ground post is main chassis ground.

Located, IMO, the best location for the fan controller. I don't want a $180 piece of electrical equipment exposed under the hood. Routing the 10 gauge fan ground and positive along the passenger side taping into the starter wire for power and the ground entering through a rubber knockout just under the PCM connections. Taking the glove box assembly out to gain better access, along with pulling the carpeting and sound dampening foam at the PCM will give you access to this rubber knockout that has a bundle of wires feeding through. They are just enough space on the side to route the fan ground, sensor, battery, & ignition turn on wires.

Add one for AC on as well if wanted. I taped the 10 gauge wire and other wires to a 10 inch long piece of coat rack so it can be punctured through the rubber and then pulled through from under the hood area once the PCM connections had been removed to gain room. Red wire shown as ground, but will replace with black when it comes and pull back through using this wire. The controller fits well inside the small space in the passenger dash corner. Easy adjustments or wiring mods can be done by popping off the plastic cover. I will still need to mock up a bracket but a ground stud is already inches from the controller as well.

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Looks clean and fits perfect nice choice...waiting in anticipation for the outcome
 
Fan came in and got it mounted inside the shroud using double zip ties per fastener and shes solid as a bolt in. Mocked up the controller in the floor board for testing and adjustments and she seems to like the middle to +1 clock wise setting so far. I'll take more pics of the controller once mounted.

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Fan came in and got it mounted inside the shroud using double zip ties per fastener and shes solid as a bolt in. Mocked up the controller in the floor board for testing and adjustments and she seems to like the middle to +1 clock wise setting so far. I'll take more pics of the controller once mounted.

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Looks like a well built fan ...very solid! Time will be the test to see how it holds up under driving conditions but this fan looks like IT WILL COOL!!!!..it fits perfect and has a high quality look for what the picture shows ...thanks for the update ...keep the posts coming on the progress
 
More testing tomorrow. I feel stupid and need to reverse the blades as a puller.
 
the only thing the fan does as installed is limit air flow through the radiator at speed. The fan has to be sealed to the shroud (preferred) or the radiator. As pictured, with fan running the air enters the shroud between the shroud and the outside of the fan and gets expelled through the fan thus not cooling the radiator. the last picture shows the temp needle over the hash mark so the coolant temp is probably about 235 degF or so. the cheapest way to seal the fan to the shroud would be to use foam such as wall mounted A/C foam sealing strips. a bag can be bought for a couple of bucks at every big box or hardware store including WM. Also, the zip ties may fail after a short time. brakets could be bent from aluminum and the fan bolted to the shroud.

another option would be to install the fan and seal it to the radiator top right corner (the input side) as that's where the radiator mounted fan will do the most good.

Another thing to do would be to get extra A/C sealing foam strips and put them between the radiator sides and the chasis so the air can't bypass the radiator.

Also use an air hose or low pressure garden hose from the back side of heat exchangers to remove crud blocking the air passages.

the air is lazy and will take the path of least resistance so it has to be guided to where it's needed.

good luck.
 
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Also if driving without the windshield wiper cowl or the A/C filter shroud where the radiator controller sits, the high pressure air from the bottom of the windshield will enter the engine bay and increase the pressure behind the radiator thus lowering the flow through the radiator.

by A/C shroud I meant not the shroud the A/C filter mounts to but the cover that sits in front of the filter and separates it from the engine bay.
 
the only thing the fan does as installed is limit air flow through the radiator at speed. The fan has to be sealed to the shroud (preferred) or the radiator. As pictured, with fan running the air enters the shroud between the shroud and the outside of the fan and gets expelled through the fan thus not cooling the radiator. the last picture shows the temp needle over the hash mark so the coolant temp is probably about 235 degF or so. the cheapest way to seal the fan to the shroud would be to use foam such as wall mounted A/C foam sealing strips. a bag can be bought for a couple of bucks at every big box or hardware store including WM. Also, the zip ties may fail after a short time. brakets could be bent from aluminum and the fan bolted to the shroud.

another option would be to install the fan and seal it to the radiator top right corner (the input side) as that's where the radiator mounted fan will do the most good.

Another thing to do would be to get extra A/C sealing foam strips and put them between the radiator sides and the chasis so the air can't bypass the radiator.

Also use an air hose or low pressure garden hose from the back side of heat exchangers to remove crud blocking the air passages.

the air is lazy and will take the path of least resistance so it has to be guided to where it's needed.

good luck.

I was concerned with the gap around the shroud and even the spacing from the radiator. After reversing the blades this morning it did made a big improvement, but the temp still climbed to 3/4 once on my way back home vs always doing it twice before in the same distance. I think my next steps are to eliminate the stock shroud and just buy an aluminum shroud and the higher performance 17'' fan I linked earlier. I will have to mock up some brackets for the AC canister and coolant pump, but that wont be too bad.
 
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Also if driving without the windshield wiper cowl or the A/C filter shroud where the radiator controller sits, the high pressure air from the bottom of the windshield will enter the engine bay and increase the pressure behind the radiator thus lowering the flow through the radiator.

by A/C shroud I meant not the shroud the A/C filter mounts to but the cover that sits in front of the filter and separates it from the engine bay.


The cowl was only out to route wiring for the controller and while taking those pics.
 
SPAL Puller 2024 CFM 16'' fan and an 23-3/4'' x 18-3/4'' aluminum radiator shroud on the way. Controller + Spal + shroud + 10 gauge wiring = $438

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New shroud and Spal high performance fan installed. Will test out later today.

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Everybody's a critic, I know. That said, it looks like it is too close to the radiator to let the airflow spread out. I think you could get a lot more airflow through the radiator if the shroud and fan where a few more inches from the surface of the radiator.
I'm no expert on airflow, but I recently had a project where we had to keep a large LCD cool when exposed to sunlight. We did a lot of experiments with fan size and placement using smoke and temperature probes. I would not have believed the different it made putting the fan on a two inch riser.
 

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