I would like to retain the stock temp guage in the car. Will I have to use 2 senders, one for the guage and one for the fan controller? Or is there a simple way to use one temp switch for both?

I think there are too many variables to allow "stock" sending units.
that is why most aftermarket setups require the chevy temp unit.

BUT... since this is temp adjustible, theorectically you could get up to temp, and turn the pot till it came on.

don't know how "common" the wave forms across mopars in general.

When we get one in, I will jumper my original sensor into it and see if it can read it just for the heck of it.

But realisically you should either tap a new hole, or use the probe type sensor listed above.
hooziewhatsit would have to comment to be sure.

As for sending that ociliscope, sure if you want. if it has capture we can do that, if not we can video tape segments for you and mail it back on dvd so you can see what you need that way. Just give me some guidelines on what you are looking for. a/c on, temp up etc.. Will have to be a static test obviously.

Feets will have to get another car side plug. I have an extra fan side plug. I guess if I have to we can canniblize his hot rod for it and hot wire the fan on full time while we run the car and extra fan through the ociliscope.

Obviously we will have to do it some day I take her car in for service instead of at home.

I'm really not sure if the stock sensor would work or not. Adding my board may or may not affect how the sensor in your dash reads as well. I'm also not sure what voltage the stock sensor uses (pulsed 5v, right?)

Like Andrew mentioned, you could hook it up, wait until the car gets to temp, then turn the pot down until the fan comes on (or until the status LED turns on, to see if it'll work). In fact, due to the small differences in temp sensors, this may be the best way for everyone to set the turn on temperature.


For the o-scope, here is the one I was thinking of getting. link

To use it, basically just need to hook one probe each to the trigger and tach lines. The software has a few settings, but by playing with it you should be able to figure it out. It looks like it does have the option to export/save data. I'd just need a copy of the waveforms at different fan speeds. Basically, put your special harness in between the fan and the plug in her car, then let it idle and warm up in the driveway. Capture some data at different speeds and you're done.

If that sounds like something you'd be willing to do, I'll get the oscope and we can go from there.

yeah, I can do that. don't see it doing any harm. not sure if you will get anything useful, but I am game.

The oscilloscope just showed up, and it's pretty cool.

I also have a couple controller boards about ready to send your way for testing. If one of you wants to PM me an address, I'll get them out by Monday.

any updates?put me on the list for a box.

hasn't gotten to me yet. there has been some bad weather here for the last few weeks, and everything is a bit delayed.
will post when I get it and some test results after I get it wired up.

got the parts today.
not sure if I will have a chance to play with it till this weekend.
but thought I would let you know it is here.

So I got a chance to test it today.
I ran an old style fan for about an hour and a half continuously with the controler. About 2 and half hours total. Way longer than anyone else has gotten one to run, and way longer then should ever be necessary to run one.
I checked the different functions of the controler.
With a ground signal instead of a temp sensor, a ground signal for a/c.
With the 2 wire temp sensor he included and all of that worked as advertised.
The temps are a bit off compaired to what my efi says it is, but that could be either set of sensors being wrong. probably off by about 5 degrees or so. The 10 degree shut off is about 12 degress, but is fine.

The orignal sensor in my car does not activate the controler at all. Not sure it is worth pursuing or not, just use the after market type that you push into the rad fins if you don't want to tap another hole I guess.

Here are some pictures.
The two controlers.


Here is a reference so you get an idea of the size.
next to a voltage reg.

this one seals better, but I still have to test the black one to see if it will work.


Black one is more compact and looks better, but not sure about weather. mounting it inside should be fine.



got the basic wiring done enough for the default without a sensor to kick in and start the fan.


laid it infront of the car.

you can't see it, but I was walking around and kept hearing this crunching noise and caught sight of the fan mulching leaves in the driveway.
It moves a lot of air.

Then my other fan kicked in and things got bad.

you might not be able to tell, but that is a 4 gauge wire. Melted at the end.
Apparently that would be a weak link in my electrical setup.
Trying to run 2 fans pushing 50 amps just isn't good for my car.

cable end.
Here is the end off the alt.

notice the melted copper?



Well I patched it up, and made sure my alternator was still charging. has a bit of smoke damage on it, but still working. So don't try that at home.
It definalty proves my electrical system works and nothing else died on the car, but wow.

Figured out a different way to setup the fan, so that it might draw air through the radiator, so both fans didn't kick on.
At first I tried to raise it infront of the car, and pull air from the engine to the front. That did not help.
Here is what I came up with.



it is laying on the air cleaner, and the radiator. About 6 inches of open space between the two is where all the air is being pulled from the radiator.

The fan moves enough air, that it kept the car at 197 for an hour and a half. actually I let the real fan cycle first taking the temp down to 189, then turned this back on. It kept it at 193 to 196 for a while then it creeped up to 197 and held there for another half hour before I called it good.

I will get some water testing done tonight or tomorrow. Will probably be next week before I get the ociliscope work done to see if we can get the fan at a lesser speed. And I may do a few more endurance tests on the old fan with the controler since I have it wired up.

Anything else someone wants me to check?

Those fans pull a constant 39 amps while running and flash to 50 amps on start up. With one fan running, add in your electric fuel pump and EFI system and you're looking at a 50 amp draw. When the second fan kicked in with a 50 amp flash your alternator was loaded down with 100 amps. That is far more than what any of us will be seeing with the exception of guys pushing eleventy billion watts worth of stereo amplifiers.

I guess that flashy stereo amplifier wiring kit you used on the alternator met it's match. A quality 4 gauge wire should be able to handle that load.
So, unless you have a killer charging system, don't run two of these fans at the same time.

Personally, I think it's awesome that the fan cooled your engine while laying on top like that. Some folks can't comprehend what we mean when we say these fans move stupid amounts of air.

I think the longest an old style (or aftermarket) fan ran wide open while wired directly was about 20 minutes. The PWM controller seems to do the trick. There is no reason one of these fans needs to run for an hour straight. Even with a blown head gasket the fan would cool the hot rod. Assuming you were caught in stop and go traffic during one of our 110 degree heat waves the fan would cycle off and on without allowing the engine to get to an overheat condition.

It's a good acid test. If the little black box does a fair job of protecting against water intrusion it'll be a winner.
If not, running two wires through the firewall would be an easy way to mount it under the dash.

Thanks for posting your findings

Now I just need to update my website and I'll post a link for where they can be purchased from. It'll be another week and a half until more components show up and I can assemble, test, and start shipping them. If you don't need/want variable speed, you can get one now. Otherwise wait a little longer until I know if I need to add hardware, or if it's just a software change.

I'm also considering making another controller that would add variable speed to any 'normal' fan that does not use a trigger wire (like the other Mercedes fan).

Just wanted to jump in here and congratulate you guys on some awesome work

Always nice tracking the development of something like this.

I'd like to come full circle on this and get some clarification.

The PWM controller is used in conjunction with the aftermarket fan, correct? The cheaper of the two units that can be found on eBay? And the PWM box is triggered by a third party thermostat producing 12V+ when it wants to turn on?

Summer is quickly approaching here in the desert and this looks like the next logical step away from the all-to-tiny Ford Taurus fan currently covering ~60 percent of the cooling surface of my radiator.

not sure about part of your question.

I tested an early model of the mercedes fan. It is built like the aftermarket fan that requires some sort of controler or it burns out after 20 min of full power.

I ran it for and hour and half continuous, probably another hour off and on. It was definatly pulling a lot of amps, as you can see by the melted alternator wire when both were running.

The controler can be triggered 4 ways. I tested 3.

You can set up some other temp setup like the stand alone adjustibles that push into the radiator fins and supply a ground to the box.

you can have a trinary switch for a/c that supplies ground to another circuit to the box.

you can have a 2 terminal standard chevy temp sensor installed and it will read off that.

or there is a single terminal temp sensor as well, which I did not test.
I did attempt to use the stock 1965 temp sensor, but that did not work.

The controler ONLY suppiles the trigger voltage to turn on the fan. The fan has to be wired to power and ground seperatly.
Both new and old style fans have built in relay's so nothing else has to be done.

That is correct. The fan I use and feets uses both can take a straight 12 volts.

The older fans and aftermarket require this controler box or the burn out pdq.

The ground is how I have my efi setup wired as well, and I setup the trinary to ground on the same wire, so it would be a simple swap for me too, as I would remove the relay and replace it with this box.

I chose to wire them up seperatly just to make sure everything worked, and it is a pain to replace my fan with the old style.

After I do some environment tests on the boxes, I may substitue my relay for a while for drivablity tests later on, but at that point it is just endurance tests for the electronics vs if it works or not.

Regardless, no way the fan will take as much abuse as I put it through in one sitting.

To clarify...

Quote:

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And the PWM box is triggered by a third party thermostat producing 12V+ when it wants to turn on?

---

The only input that can take +12v is the AC input. That input can either be grounded, or given +12v, to turn the fan on.

The temperature sensor input can only be grounded, or be hooked up to the temp sensor.


My website is now updated and ready to take orders
http://www.ma-uav.com/FanController.html
I have two controllers in stock, with more about a week and a half away. I'll get a thread in the new products section once I get more in stock.

If you don't want/need variable speed, order away. Otherwise wait a week until I know more about the changes needed.


Andy/feets: Does the newer fan also have a trigger wire? Is this an example of that fan? link

wiring is exactly the same, new or old style.

looks correct for the new style. and, though it isn't needed, unless someone wants variable speed, if you get that to work, I verified you controler will turn that type on and off too.