New Electric fan :) low voltage :(

my66coupe · Sep 20, 2004

Well, Instead of buying a 3 core radiator, i went the cheaper way and bought a electric fan, install was simple and quick. For the wiring i grounded on the voltage regulator where other grounds were located. For power, I went inside under the dash, where the yellow 3 splitter femal port is, Im not 100% positive on this being a 12 volt sorce, but i have my radio, and my mechanical guages(backround lights that are on at all times) running off of it, and they work fine. Ok soo the story is, with the install of the fan, and the fan being activated only when the ignition switch is on or at acc......my voltage guage only reads a little over 10 volts, if i get it off idle and around 2 grand it goes up to 12 and if i rev it higher it will rev to about 12.5 and start bouncing back like a rev limiter......Soo my question is, should i get power from the battery, and just splice in a switch? Or did i do something wrong and i should be running fine???? Thanks guys....

Mike

Btw, the fan is keeping me in the 210-230 range....The other day I hit 260 with my flex fan.

Route666 · Sep 21, 2004

That fan most likely draws a fair bit of amperage. You should wire a relay to the ignition source, and have direct power from the battery to the fan.

WORTH · Sep 21, 2004

What the Route Devil Said

rbohm · Sep 21, 2004

not only shoud you run a relay in the system, BUT you should also upgrade to a 100amp alternator. the fan is drawing all your current and then some which is why you are reading such a low voltage.

ForceFed70 · Sep 21, 2004

Another vote for a relay. Then you can wire directly to the battery, yet still have it turn on/off with the ignition.

As for upgradeing the alternator... I'd keep an eye on my voltage guage for a while and see if it's dipping below 13.5V while driving with headlights, Fan, radio, etc on.. before doing the upgrade.

stangman67 · Sep 21, 2004

I did the flex to electric swap using a relay and temp controlled switch. If your car hit 260 with the flex, you have different problems like a bad radiator, or stuck closed tstat, or maybe a pure eg coolant mix. After I put mine on, normal flex fan temps went from 160 up to 180. The fan was a permacool 16" with 2950 cfm. The longer it idles, the higher the temp gets. I have seen 210 on a hot day idling, while the flexer kept it at 160. And def. use a relay with full battery power.

my66coupe · Sep 21, 2004

Well with heavy mods, a 2 core radiator, and 110+ degrees outside. im sure ive pinpointed my problem. With the electric fan, ive been keeping cool....Soo by meaning relay, I should run....wire from the battery into the dash, to a switch, a fuse in between the wire. then power from the switch to the fan itself and im done? thanks guys

Mike

WORTH · Sep 21, 2004

my66coupe said:
Well with heavy mods, a 2 core radiator, and 110+ degrees outside. im sure ive pinpointed my problem. With the electric fan, ive been keeping cool....Soo by meaning relay, I should run....wire from the battery into the dash, to a switch, a fuse in between the wire. then power from the switch to the fan itself and im done? thanks guys

Mike

AAAAAAAAHHHHHHHHHH,,,,,,,,,,,,,,,NO, you need to run a switch to operate a relay that will put battery voltage to the Fan motor.

ForceFed70 · Sep 21, 2004

WORTH said:
AAAAAAAAHHHHHHHHHH,,,,,,,,,,,,,,,NO, you need to run a switch to operate a relay that will put battery voltage to the Fan motor.

Lol.. your both on crack!

With a relay you don't need to add a switch. Your ignition switch is all you need.

Mike: Here's what you do.

-Find a place near your battery/fan to mount the relay.

-The relay will need 4 wires run to it.
1) Fused power straight from battery.
2) A ground wire from wherever you want.
3) Power wire from relay to fan.
4) Switched ignition power. This can come from the source your currently using, from the + side of the coil (9volts will throw the relay no problems), or even from the voltage regulator for your alternator. Just test with a voltmeter to make sure it has +12V when the key is turned to "run" and 0V when the key is off.

You can think of a relay as simply a "voltage controlled switch". Give it some voltage and it will turn the switch on/off depending on how you wire it. The beauty of a relay is that you can switch many amps (typicaly 30amps on an automotive relay) of current, with only a small supply current to throw the relay/switch (typically about 0.25amps for automotive relay) Your starter solenoid for example is basically just a big relay.

gp001 · Sep 21, 2004

Just to add a small visual to 70_Nitrous_Eater's advice here is an image of my fuel pump relay setup I did for someone a while back. Just replace the word "pump" with the word "fan" for terminal 87, and just use an ignition 12 volt source, a thermostatic switch, or a toggle switch on terminal 86

As stated, mount the relay close to the battery. Then, when you apply 12v to terminal 86 (which has low amp draw) the relay will allow 12v (high amp) to pass through the relay from terminal 30 to terminal 87, and out to the fan. The shorter you make the path from the battery to the fan the better (lower resistance). The length of the wire to terminal 86 doesn't matter because it is a very low amp 12v draw.

Also, always use appropriate gauge wire

mdjay · Sep 21, 2004

Do what they said on the relay first...

However, I never recommend going to an electric fan without the consideration of your electrical system. These cars don't put out very many amps stock and the regulators flat out suck.

Second, I would make sure I had good ground straps from the motor to the firewall and the motor to the mounts.

If you are still reading a low and/or bouncing reading for voltage, throw the regulator in the trash can, get a solid state one (around $50), and upgrade the alternator to at least 85 amps.

ForceFed70 · Sep 22, 2004

Thanks GPOO1:

I've got a question about your setup however. Looking at that wireing diagram, it looks like you wanted to fuel pump to work only when the key is on, the kill switch has NOT been thrown, the inertia switch has NOT been thrown, and that the engine has oil pressure. Looks good.

So here's the question.. Do you have to crank the engine for a while to build oil pressure and THEN have the fuel pump kick in to start the engine? How long does this take?

gp001 · Sep 22, 2004

70_Nitrous_Eater said:
Thanks GPOO1:

I've got a question about your setup however. Looking at that wireing diagram, it looks like you wanted to fuel pump to work only when the key is on, the kill switch has NOT been thrown, the inertia switch has NOT been thrown, and that the engine has oil pressure. Looks good.

So here's the question.. Do you have to crank the engine for a while to build oil pressure and THEN have the fuel pump kick in to start the engine? How long does this take?

No, with the 3 wire (*cough* GM *cough*) version you do not need to build oil pressure. The S terminal provides a bypass. The "S" terminal is wired to the start circuit, and the "I" to ignition.

WORTH · Sep 22, 2004

"Lol.. your both on crack!

With a relay you don't need to add a switch. Your ignition switch is all you need."

Maybe you've been snorting too much nitrous, but the reason I used the term switch is because you can use a toggle, the ignition switch, or a thermostatic switch. The ignition switch being my last choice. The best would be thermostatic and second a toggle.

Oh,,, I prefer Capt. Morgan for a high.

Route666 · Sep 22, 2004

Yarr the good old captain. For a very piratey experience I prefer frigate overproof rum. Cheap, nasty, and very ARRR!!

Anyways I second / third having a thermostatic switch, combined with the ignition. It's a waste of power having it on while cruising, you don't need it on then.

GaPonyFarm · Sep 23, 2004

Use a relay and thermostatic switch, connected to the battery and be done with it. When you park the fan will continue to run for a few minutes to cool the engine... Almost everyone forgets to flip a toggle switch, from time to time, which would be a disaster. The ignition switch on early mustangs is already overloaded, unless you've rewired.

Get at least a 100 amp alternator and an optima red top battery.

New Electric fan :) low voltage :(

my66coupe

Route666

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WORTH

rbohm

ForceFed70

That's why they call it "dope"

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my66coupe

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ForceFed70

That's why they call it "dope"

gp001

mdjay

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That's why they call it "dope"

gp001

WORTH

Route666

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GaPonyFarm

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New Electric fan :) low voltage :(

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