Need electric fan help

[LA_phantom_240]

Okay, I bought myself an electric fan setup where I work, and need some help wiring it up. I have a 95 s14, and I can't identify which is my main ignition relay. Is there any suitable relay under the hood? It has a thermostat control, which goes between the ignition relay and the fan relay. I'm thinking I can wire up the lead that goes to the ignition relay directly to the battery, seeing as it won't turn on unless the coolant goes over 170 degrees anyway... and shouldn't come on while the car is off. I realize that if I go over 170 degrees and turn the car off, the fan will stay on until the thermostat tells the fans to turn off, which shouldn't be that long either. My coolant gauge rarely gets past 1/3 of the way up anyway... I think I'm missing a thermostat.

Anyone have any suggestions?

[burnsauto]

i usually just run them off the battery/positive terminal (if its in the trunk) and then just ground it to the chassis. never had a problem with it.

[LA_phantom_240]

Sounds good. Ima go take off my hp stealer... I mean clutch fan.. lol.

[IStop4NoMan]

i dont have much input but i can say, dont trust the stock gauge! get an aftermarket one and put it in the rad hose. you will see what the REAL temp is like. mine normally chills at 180 degree and thats when both fans come on. when it reaches 190, i know i have a problem, but you wont see those kinds of changes with the stock gauge. i know i sound picky, but my fans dont always work, and i know a 10 degree change means they arent working:ugh:

[LA_phantom_240]

Yeah, definitely getting a good temp gauge. For some reason, my fan isn't coming on when I think it should be. For instance, the temp gauge climbed up to the top line, just before hitting H while idling for a good 20 minutes. The thermostat switch didn't turn it on, so I used the A/C override function and she cooled off within a minute or so. Any reason that the thermostat switch didn't work? I have it hooked up like the diagram says...

[g6civcx]

Read very carefully:

1) Never ever piggy back on an existing circuit. You will fry your wire = bbq = dead S14 owner.

Go get yourself a 30A relay and search on Google to learn how to wire it up.

2) Never ever trust the stock temp sensor. It's a 2 stage switch where middle is anywhere from 110-250. If you see Hot it's way too late.

3) You need a good fan controller. Go to FRSport and read their fan controller install to get an idea.


Again, wiring this up is not hard but it's not easy if you don't have experience.

Right now do some homework and come back if you're stuck.

[LA_phantom_240]

It is a relayed system. The turn on (pin 85 IIRC) has 2 wires coming from it, one that runs to the thermostat probe switch, and one that you can wire up to a switch, or the stock electrical fan or the A/C compressor clutch.. which is the A/C override function.

[g6civcx]

It is a relayed system. The turn on (pin 85 IIRC) has 2 wires coming from it, one that runs to the thermostat probe switch, and one that you can wire up to a switch, or the stock electrical fan or the A/C compressor clutch.. which is the A/C override function.

It's a standard 12V 30A automotive relay available at any parts store. It has 4 or 5 pins: 85, 86, 87, 30.

85, 86 - these are the control pins. Applying current to one and ground to the other. It doesn't matter which is which. Make sure your control signal doesn't exceed 30A so put a 30A fuse in front of it if the control signal itself doesn't have a fuse already.

30 - this is the power pin. It comes straight from the battery. Make sure you put a 30A fuse in front of this pin.

87a - this pin is hot when there is no current across 85-86.

87 - this pin is hot when there is current across 85-86


For the rest on how to wire a relay search on google.

Make sure you use at least a 12 gauge wires on 30 and 87-87a. Anything smaller won't be able to pull 30A.

The 85-86 control pins can have smaller wires if the control signal is low amperage.

fan relay wiring:

85-86 one goes to the fan controller pin that's how when the fan is supposed to turn on, the other goes to ground.

30 - put a 30 fuse in front of this and connect it straight to the battery with at least a 12gauge wire

87 - 12 gauge wire to the positive terminal of the fan

make sure you ground the fan motor as well.


The fan controller itself usually has a pin for constant power, ground, fan turn on signal, and probably an AC signal and a manual switch.

Make sure you put a fuse in front of the constant power pin and connect it straight to the battery.

Make sure you pick a good ground.

The fan turn on signal goes to the standard auto relay discussed above. Either pin 85-86 will do.



AC signal goes to the compressor switch that turns on the condenser fan whenever the compressor clutch engages.
Manual switch goes to a 30A switch.

These two control signals may be active hot or grounded hot. That means when you activate the signal, you can either supply power to the fan controller, or you can ground the signal. It depends on how your fan controller is set up. Some of them has a toggle setting.
Usually they're active hot. If that's the case, the switch goes like this: battery - 30A fuse - 30A switch - fan controller with 12 gauge wires.


I'm making wiring diagrams for myself and I'll share them later. It's really pointless without pix.

[LA_phantom_240]

Civic, dude, I know how to wire up a relay. That's not the problem here. Trust me, I use relays for LED setups and shit. The thermostat switched fan controller kit HAS a relay. It is hooked up via the relay.

[g6civcx]

Civic, dude, I know how to wire up a relay. That's not the problem here. Trust me, I use relays for LED setups and shit. The thermostat switched fan controller kit HAS a relay. It is hooked up via the relay.

Don't take offense. It's really meant for everybody who has the same problem so they don't ask the same question. Besides, nobody knows what you do or don't know. Everybody claims to know everything until they have problems.

Measure the 2 pin temp sensor. The best way is to remove the sensor and place it in a pot of boling water with a thermostat. Then measure the change in resistance as the water temperature changes.

I don't know what range it should be but at least you'll know if it doesn't work for a range of temperature.

At very least watch what happens as the temperature go up to 200 and see if the signal changes. If all of a sudden at 200 it starts putting a different reading then you know the sensor is bad.

If the sensor changes signal as temperature goes up, then your fan controller is bad.

[LA_phantom_240]

Hmm... Taking the probe off right now blows cock, but I guess that's the only way to get the fan to turn on.

This is a total noob question, I know (because I've never had to deal with this), but which side of the radiator is the inlet and which is the outlet, top or bottom? Right now the probe is close to the center of the radiator (left or right), close to the bottom, out of plain sight. Should I move it closer to the top, and maybe it will get hotter than it is and let the fan turn on?

[g6civcx]

Hmm... Taking the probe off right now blows cock, but I guess that's the only way to get the fan to turn on.

This is a total noob question, I know (because I've never had to deal with this), but which side of the radiator is the inlet and which is the outlet, top or bottom? Right now the probe is close to the center of the radiator (left or right), close to the bottom, out of plain sight. Should I move it closer to the top, and maybe it will get hotter than it is and let the fan turn on?

I have no idea what your problem is at this point. Your first post looks like you don't know how to wire up anything. Your second post looks like you don't know how to wire up a relay. Your 2nd to last post claims you know how to use a relay.

I'm trying to help you but you're not answering the question with the correct information. You claim to know but yet your comments seem like you don't know.

At this point you need to a do a complete check of the system. Do a search and make sure all your wires line up correctly, are of the correct gauge, and have appropriate fuses and relay hookup.

The lower radiator hose goes into the engine because gravity pressurizes coolant. The upper radiator hose feeds coolant into the radiator.

Think about it. It won't work the other way. If you put coolant into the bottom of the radiator and try to suck it through the top, the water pump will have to work extra hard to suck all that coolant up. Plus any small loss in coolant and you'll lose cohesion/adhesion and it'll be difficult to suck it through the top hose.

Put the sensor as close to the water outlet on the engine as possible to get the most accurate reading. Put it too far away and the coolant will cool off, giving a lower reading.

These are very fundamental questions. If you search 5 minutes on Google you will find the answer.

Just wait until Russ comes back from Thanksgiving and he'll hammer me for spoonfeeding you.

[LA_phantom_240]

I think the probe positioning is where I'm going wrong. Its too close to the outlet. As far as the wiring for the relay, it came from the factory with color coded wires and a diagram. The relay (pin 85 or 86) and fan are both grounded directly to the battery, there is a positive running from the battery to the thermostat probe/switch, which runs to the relay (pin 85 or 86, polarity doesn't matter here). There is a wire on that same pin which is used for A/C override, where when you switch the A/C on, it turns the fan on, regardless of coolant temp. Under normal operating conditions, the relay should be turned on by the probe/switch. This is not happening, but it can be turned on using the A/C override lead, indicating that the relay is functioning. I can also hear it click. And of course, the fan's positive is hooked up to pin 87, which is switched to get power from pin 30.

[g6civcx]

I think the probe positioning is where I'm going wrong. Its too close to the outlet. As far as the wiring for the relay, it came from the factory with color coded wires and a diagram. The relay (pin 85 or 86) and fan are both grounded directly to the battery, there is a positive running from the battery to the thermostat probe/switch, which runs to the relay (pin 85 or 86, polarity doesn't matter here). There is a wire on that same pin which is used for A/C override, where when you switch the A/C on, it turns the fan on, regardless of coolant temp. Under normal operating conditions, the relay should be turned on by the probe/switch. This is not happening, but it can be turned on using the A/C override lead, indicating that the relay is functioning. I can also hear it click. And of course, the fan's positive is hooked up to pin 87, which is switched to get power from pin 30.

I see several potential problems with this:

1) What brand is the thermostat? Does it have a control box or is it a probe with a built-in sender? Did you put a fuse between the battery and the thermostat?

2) Can you post the wiring diagram? Why did you decide to connect the AC signal to the same pin as the thermostat? Did the factory tell you to do this?

3) I really hate those through core thermostat. They are not accurate. If you insist on using it at least put it as close to the upper radiator hose as you can.


Try this. Disconnect the AC signal from the relay and see if the thermostat can control the fan relay by itself. If it works normally like that, then you'll need to use a diode between the AC compressor and the relay.

[LA_phantom_240]

1) The thermostat brand is the same as the fan: TorqFlo. It has a built in sender/switch on the probe. There is no fuse between the thermostat and the battery, because as you should know, there is no need seeing as it requires very little power to turn a relay on, which is all the switch does.

2) The A/C override is on the same pin as the thermostat because the pin they're on is the positive lead on pin 87, which only serves to open or close the relay. Pin 86 has the ground. There are 2 ways to turn the fans on, with the thermostat, or with the A/C override, so they MUST be on the same pin to function. The harness is pre-wired from the factory.

3) I am going to reposition the probe as soon as it becomes necessary. Its cold and rainy here in Louisiana, and taking out the radiator takes a little bit of work. Its not hard by any means, just time consuming when you're in the cold rain. The car isn't overheating AT ALL, and in fact she still runs cooler than normal, leading me to believe there is no thermostat in my cooling system, which isn't all bad. When it warms up a bit, I'll see how she goes.

The A/C override is not currently hooked up to anything. I will, however, find a pinout for the factory electric fan that comes on with the A/C and use that as my turn on for the A/C override. It doesn't need a diode because it is an incomplete circuit, seeing as the factory connector for the A/C fan is no longer grounded, and I'm only using the 12v lead to turn on the fan when the A/C comes on. Think of it as a remote turn-on lead for an amplifier. This is essentially the function of the relay, and the A/C override being hooked to the factory harness for the factory A/C fan.

See where I'm coming from now?

[g6civcx]

1) The thermostat brand is the same as the fan: TorqFlo. It has a built in sender/switch on the probe. There is no fuse between the thermostat and the battery, because as you should know, there is no need seeing as it requires very little power to turn a relay on, which is all the switch does.

This is not true. Any time you draw power from the battery you should put a fuse in front of the accessories, even if the current draw is very little. This is to protect it from spikes in the current that can fry your relay.

2) The A/C override is on the same pin as the thermostat because the pin they're on is the positive lead on pin 87, which only serves to open or close the relay. Pin 86 has the ground. There are 2 ways to turn the fans on, with the thermostat, or with the A/C override, so they MUST be on the same pin to function. The harness is pre-wired from the factory.

And I told you to remove the A/C signal to see if drawing current from the thermostat. That relay is wired to have the AC signal sender generate high impedance when the AC is off, and 12V(+) when the AC is on. If your AC signal sender generates 12V(-) when the AC is off, current is being drained from the thermostat and never makes it to the relay.

You should have diodes in front of the AC compressor and the thermostat to prevent current backwash which may damage the component.

That factory wiring is crap unless it has an OR gate between the AC compressor and the thermostat.

If the 2 wires just merge at the relay then it's going to give you problems.

am[/I] going to reposition the probe as soon as it becomes necessary. Its cold and rainy here in Louisiana, and taking out the radiator takes a little bit of work. Its not hard by any means, just time consuming when you're in the cold rain. The car isn't overheating AT ALL, and in fact she still runs cooler than normal, leading me to believe there is no thermostat in my cooling system, which isn't all bad. When it warms up a bit, I'll see how she goes.

How do you know it's running normally? As said above and posted thousands of times before, the stock temp gauge is not accurate at all. You could be overheating without even knowing unless you have a good aftermarket temp gauge.

The A/C override is not currently hooked up to anything. I will, however, find a pinout for the factory electric fan that comes on with the A/C and use that as my turn on for the A/C override. It doesn't need a diode because it is an incomplete circuit, seeing as the factory connector for the A/C fan is no longer grounded, and I'm only using the 12v lead to turn on the fan when the A/C comes on. Think of it as a remote turn-on lead for an amplifier. This is essentially the function of the relay, and the A/C override being hooked to the factory harness for the factory A/C fan.

See where I'm coming from now?

This part confuses the hell out of me. Before you said the AC signal is turning the fan on. Now you say it's not connected.

I still think your switch is shorting out the thermostat signal. I gave you at least 5 things to check but you don't want to do any of them.


I'm leaving this thread alone. This is very simple circuit design but you seem to be fighting me instead of giving clear answers. Good luck.

[LA_phantom_240]

The A/C override is NOT hooked up right now. The wire is sitting in the engine bay, rolled up and insulated by electrical tape. When I touch the override to the battery positive, the relay clicks and the fan turns on.

And about the stock gauge, I know its not accurate, but getting 1/4 of the way up is telling me that it is running cooler than normal. Also, I can physically feel the difference in the radiator. Under normal circumstances (an s14 with stock fan and thermostat), the radiator is pretty hot at operating temperature. Mine, however is only warm to the touch, and you can actually take the radiator cap off without having a shit ton of coolant spray out at you. It just dribbles a bit, which also says to me that it is , again, running at less than normal operating temperature.

I'm not trying to fight you, but rather I'm trying to make sure we're on the same page here. I feel like you're misunderstanding what I'm trying to explain.