How To: Install Electric Fan WITHOUT going aftermarket (Let the PCM do the cooling!)

[NICE59FORDF100]

At slow vehicle speeds the fan is important for cooling the engine coolant via airflow thru the radiator and making the A/C cooling adequate via airflow thru the condenser. I wonder if the VLCM monitors the IAT and compares that with the desired cabin temperature versus the actual cabin temperature and adjusts the fan speed accordingly. Or it may just assume that if the vehicle speed exceeds a certain value the airflow thru the condenser is adequate and there is no need to run the fan. I agree with Maniak that most of the fan control problems are integrating the A/C cooling, engine cooling, and fuel economy. I think the electric fan on my 1996 Volvo 850 Turbo Wagon is a two speed (off, low, high) with a fairly dumb controller but seems to work fairly well. I know that it responds to engine coolant temperature. I don't know if it is vehicle speed dependent.

Being older Ford programming, I am inclined to believe the later statement that it will just have predefined values based off inputs (VSS, ECT, IAC, AC Request) and adjust the fan speed accordingly. The VLCM doesnt have any input for EATC stuff (Auto HVAC inside the cabin) so it will most likely just assume when the condensor needs extra airflow based on the PID values IMHO.

 

[Kris Guilbeaux]

Is it installed yet.. Nope still on the garage floor..

 

[arco777]

you actually trust this computer controlled garbage?

what i posted is how i used an electric fan in a non-computer car. (1985 Corvette)

The 1985 year would have had a Bosch-designed Tuned Port Injection system. It's a "computer" car alright...

I can understand people who grow up with carbs prefer the simplicity. Some guys swear by points type ignition systems too. This thread is not the place to debate what's better. If you can't support someone's efforts and be positive, butt out.

By the way, I have used the Hayden controller. I wasn't impressed with it. Not only can it not handle the Mark VIII/Taurus fan, even with a remote relay setup, but the overall quality is poor for what it costs. It's good at failing in a spectacularly stinky way. I would love to read about a documented better (and cheaper, being available from a junkyard) option for fan control. I'm sure hundreds of Fox Mustang owners would too, and other groups who use this fan but have to resort to a switch or an engine driven fan because they can't afford a high end "monster" controller.

 

[BrooklynBay]

Does it have one large fan or two small fans? If it has two small fans, then this could be part of the control system where one fan is on when there is less of a demand for cooling, and both fans when there is a high demand for cooling. Do you know what the maximum amperage usage is for the fan?

 

[GETDATSTUFF]

Subscribing,
Looking forward to seeing how this works out, I would love to ditch the hadyen switch that at times has a mind of its own, like when it thinks I need the fan on when its 30 degrees outside and I just started it up. Takes forever to warm up on the way to work when it does.

 

[arco777]

Does it have one large fan or two small fans? If it has two small fans, then this could be part of the control system where one fan is on when there is less of a demand for cooling, and both fans when there is a high demand for cooling. Do you know what the maximum amperage usage is for the fan?

The Mark VIII/Taurus 3.8 fans are a single large fan with 3 wires (NICE59FORDF100, correct me if you have a different model). One wire is a common ground, one is high speed circuit and one is low.

Amp draw claims vary but one thing I can say for sure is that if you try to only power the high speed circuit from a stop, the amp draw spike is HUGE. On the order of 70-90 amps. Continuous draw is reasonable, I believe around 20A on high speed. I have run it off a no-name 40A relay but the relay really does not like the spikes and will fail within a week or two. Starting the low speed circuit and switching to the high speed circuit after spin-up would seem to be a better plan, and there are some aftermarket controllers made for this fan that do just that. They cost a lot of money though.

 

[Maniak]

Not all of the Mark VIII fans are 2 speed. The one on my van is a single speed. I cannot post the vid on my phone but I have a youtube vid showing the amp draw. 60ish amps on startup and 30ish when running.

So far my hayden controller is working great. I hook it up different than most people. I have it watch the radiator output and run the fan only when the radiator output reaches 165f or higher. It never runs on the freeway and the motor comes up to temp fast.

~Mark

 

[BrooklynBay]

Are there any solid state controllers which use power transistors with pulse width modulation control instead of switching relays?

 

[Maniak]

<snip>I cannot post the vid on my phone but I have a youtube vid showing the amp draw. 60ish amps on startup and 30ish when running.
<snip>
~Mark

I'm at a computer now. Here is the video of the amp draw using the Hayden to trip a Bosch 75 amp relay..

http://www.youtube.com/watch?v=gWJFzAMsIlc

Hopefully the variable thingy from the Mark VIII will take care of that.. It would be nice not needing the 75 amp relay.. they aren't cheap and you can't just find them at an autoparts store.

~Mark

 

[NICE59FORDF100]

The Mark VIII/Taurus 3.8 fans are a single large fan with 3 wires (NICE59FORDF100, correct me if you have a different model). One wire is a common ground, one is high speed circuit and one is low.

You are correct bud. There were, however, a couple different designs to this though. The most common is a two speed fan (the one with ground, low speed, and high speed) usually found on the tauruses (tauri?), cougars, and thunderbirds. the early MK VIII's had this as well. Then I believe in 94, MK VIII went to a single speed fan with three wires (ground, High speed, and one that isnt used). They did this not because they didnt need a low speed, but because the VLCM varies the speed, so in reality, it's an infinate speed fan. The VLCM simply varies the voltage to the fan (possibly keeping the current linear to prevent voltage spikes, hense the use of a 40 amp fuse for power?) so that the speed is never just low or high, but ranges in all different speeds. I think it is because of this why the solid state nature of the VLCM is ideal to control the fan (it had to be, thats they way for made it from the factory!).

Thoughts?

 

[BrooklynBay]

That model VLCM might be a PWM solid state controller without relays.

 

[NICE59FORDF100]

That model VLCM might be a PWM solid state controller without relays.

I believe that's exactly what it is

 

[BrooklynBay]

I wonder if the controller has an internal cooling fan to prevent the power transistors from over heating. They are under a constant load just like a desktop computer's power supply. The case should have heat sink grease, and be grounded to the body to dissipate heat. My van uses an external TFI module, and its case looks like a big heat sink.

 

[NICE59FORDF100]

I wonder if the controller has an internal cooling fan to prevent the power transistors from over heating. They are under a constant load just like a desktop computer's power supply. The case should have heat sink grease, and be grounded to the body to dissipate heat. My van uses an external TFI module, and its case looks like a big heat sink.

I don't think it does, but it is mounted in front of the core support on the MK VIII behind the grille, so most of the cooling it needs is probably just airflor from the front of the vehicle, which is where I will most likely add it on the explorer (Being there is PLENTY of room behind the grille of an explorer)

 

[BrooklynBay]

It would be interesting to see an internal view of the module before you install it. Do you have access to a frequency counter, and an oscilloscope to monitor the output (reverse engineer to see the range of the module)?

 

[NICE59FORDF100]

It would be interesting to see an internal view of the module before you install it. Do you have access to a frequency counter, and an oscilloscope to monitor the output (reverse engineer to see the range of the module)?

I do actually, that's how I was planning on testing it's output. The Ford WDS has a built in oscilloscope function that can record and view frew, amp, voltage, ect ect. It's a great scanner, and a even better electronics tool

 

[NICE59FORDF100]

It would be interesting to see an internal view of the module before you install it. Do you have access to a frequency counter, and an oscilloscope to monitor the output (reverse engineer to see the range of the module)?

Here's an internal view of one:

 

[NICE59FORDF100]

Further research does indeed need the addition of one sensor, the A/C pressure cutoff switch, for high side pressure monitoring of the AC system in a first Gen. Second gens do not need this added because there is already one installed. So as far as this whole setup working in a second Gen, I'm about 90% sure it will with a 97-98 VLCM

 

[2000StreetRod]

monitor rpm?

I notice there is a low speed and high speed fuel pump. There is a relay driver for the high speed pump. I wonder if the low speed pump rate is varied by the control module similar to the fuel pump in 3rd generation Explorers. If so, the control module could monitor engine rpm or maybe calculated engine load. I doubt that fuel pressure is available.

A 40 amp fuse for the cooling fan probably means the designed max current draw is around 30 amps. Is the Mark VIII cooling adequate in warm weather, with the A/C running and in city traffic?

 

[NICE59FORDF100]

I notice there is a low speed and high speed fuel pump. There is a relay driver for the high speed pump. I wonder if the low speed pump rate is varied by the control module similar to the fuel pump in 3rd generation Explorers. If so, the control module could monitor engine rpm or maybe calculated engine load. I doubt that fuel pressure is available.

Take a look at part of the EEC wiring below. There is only one fuel pump, but why is there something called high speed and low speed? High speed looks like a full 12 volts, where as low speed could mean like you said, the fuel pump speed is varied based off of the VLCM?