Do I have it wired right? - Corvette Forum : DigitalCorvettes.com Corvette Forums

t_l75 · 12-13-2012, 11:48 AM

Since I installed my dual electric fans, I added a thermostatically controlled switch, its supposed to go on at 185 and off at 170. However I have ran the engine over 200 and nothing happens. I have grounds at the fans, and also at the thermoswitch. What I have heard is if you have it wired correctly, and take the wire going to the thermoswitch and ground that wire, it should switch the fans on. Is this correct? because I have tried this and nothing happened. All of you EE's, what should I check next? Ive already reread the instructions and everything seems to be correct. The only thing I can think of is there are two yellow wires included that you can run to a auxiliary switch for manual turning on if you want. I havent ran a switch yet, so those wires are just free. If im not running a switch, what should I do with them? are they causing a misconnection in the circuit?

t_l75 · 12-13-2012, 11:50 AM

Here is the diagram included that I have used as a reference to wire the fans.

graphicjunki · 12-13-2012, 12:28 PM

Looks to me like the yellow wires are to go to the ignition switch to tell it when to become live.... But I'm no EE!!

Bill Davies · 12-13-2012, 12:31 PM

In the diagram, it shows the yellows going from the relays to the Ignition switch (center/bottom of diagram). The optional switch wire isn't color coded and is represented on the diagram as a dashed line (top/right of diagram).

So if I'm not mistaken, splicing the yellows into an ignition switched 12v wire will make your fans work.

1963SS · 12-13-2012, 12:38 PM

[QUOTE]I have grounds at the fans, and also at the thermoswitch.[/QUOTE]

You don't have the switch grounded.....do you? In any event, the diagram looks weird to me. It appears that the battery voltage (Big red wire) is going to the coil of the relay and it appears that the coil is in series with the fan. I don't see how that can work....at all. I've been involved with electricity/electronics and industrial controls for a long time and that just doesn't look right.

The two gray wires should be under one terminal to the switch and the yellow wire should go to the coil, not the contacts. The red and the purple wires should be on the contacts and not the coil.

It appears to me that when the thermoswitch closes to turn on the fans that it would blow the ignition fuse. Maybe it's just the new math or possibly you have some Chinese instructions. They don't like us.

Anyways, what I would do is tun the big red wire to one side of the N.O. (Normally open contacts.)

Run the purple wire to the other side of the N.O. contacts.

Run the ignition wire (Yellow) to one side of the coil

run the other side of the coil to the thermoswitch.

One side of the relay coil will have power when ignition is on.
when the thermoswitch closes the coil will energize and close the contacts.
Since one side of the contacts is voltage from the fuse and the other side goes to the fan.....the fan will turn on if the fan (-) wires are grounded. The optional switch just does the same thing as the thermoswitch. It grounds the relay coils and closes them.

The instructions look wrong to me but maybe someone has a better idea.

t_l75 · 12-13-2012, 01:12 PM

Hmm interesting... The relays came with the wires already attached, so all i did was basically run the power, switch,a nd power and ground to the fan hookups.. Ill definently have to look at it more... So your saying if I splice the yellow wires onto the HEI coil that will allow it to complete the circuit for power? am i understanding this correct?

With the way the fans are wired right now, if I add a hot wire to the fans they will power on... I just cant get them to turn on when theyre supposed to

1963SS · 12-13-2012, 01:33 PM

Quote:

So your saying if I splice the yellow wires onto the HEI coil that will allow it to complete the circuit for power? am i understanding this correct?

Whoa!!! No not the HEI coil. I'm talking about the coil of the relay. I didn't know that it was already wired. Since that's the case.....I'm confused but I still think the diagram is wrong.

Your pre-wired fan relay should have 4 wires on them. Two small and two bigger wires. The small wires go to the coil of the relay and not the HEI. Sorry for the misunderstanding.

The smaller wires on the pre-wired fan relay should go to the thermoswitch and the Ign. power.

The bigger wires should go to power from your fuse (Red) and to your fans (purple).

It ight be time to get a tester. I'm calling Summit now. I'll get back to you.

What's the part number of the fans kit??

t_l75 · 12-13-2012, 01:42 PM

Great Thank you. Im just still confused as to how the relays arent wired right from the start. But I can look at it more. I suppose I will have to add those yellow wires to a ignition source as well.

blckslvr79 · 12-13-2012, 01:43 PM

I'm feeling the love here.

This is what internet forums are all about guys!

Quote:

Originally Posted by t_l75

The only thing I can think of is there are two yellow wires included that you can run to a auxiliary switch for manual turning on if you want. I havent ran a switch yet, so those wires are just free.

Your issue is that the two yellow wires need to be run to a 12V source to power the relays.

Without this 12V source, your relays are not functioning, they are locked open, and the power is not moving through the relay to your fans.

Yes. Grounding the grey wires should trigger the relays and turn on the fans. (Assuming the two yellow wires are hooked up to 12V power)

Yellow wires need to go to switched 12V just to power the Relays on. (Ignition)

The relays are basically just a bypass switch that allows the higher voltage from the battery to pass through when triggered by another source (thermo switch) so that the entire voltage is not drawn through the ignition switch system.

The heavy gauge wire is sending power from battery to your fans. The relay is a switch in the middle of this road. The thermoswitch is a switch that triggers the relay to close and allow that power to move through. The yellow wires are 12V that provide power to the relay switch allowing the relay to function internally.

This same wiring setup is used to power aftermarket driving lights with a dash switch in place of the thermo switch and can also be used to power your headlights on the C3 so that you get more voltage to your headlights and a brighter light output. The relay allows more voltage to get to your electrical device without over loading your headlight switch.

More voltage equals higher light output. Or in this case, fan working without overloading an auxillary switch. The relays are a switch than can handle more amperage than a normal dash switch or your thermal switch. Am I rambling?

KacyC3 · 12-13-2012, 02:08 PM

What kind of kit did you buy, I've heard the only thermo switches that are worth anything are from painless.

1963SS · 12-13-2012, 02:08 PM

If you follow the written instructions you should be fine. Just make sure that the red wires go to your battery (Fuse) and the purple wires go to your fans. Leave the small yellow and gray wires off for now. Okay, now since they're off go ahead and touch them (yellow and grey) to the battery. I doesn't make any difference but go ahead and touch the yellow to the battery (+) and the gray to ground. That should energize the relay and make the fans turn on. Once we get there we can go a little further.

blckslvr79 · 12-13-2012, 02:20 PM

Quote:

Originally Posted by 1963SS

If you follow the written instructions you should be fine. Just make sure that the red wires go to your battery (Fuse) and the purple wires go to your fans. Leave the small yellow and gray wires off for now. Okay, now since they're off go ahead and touch them (yellow and grey) to the battery. I doesn't make any difference but go ahead and touch the yellow to the battery (+) and the gray to ground. That should energize the relay and make the fans turn on. Once we get there we can go a little further.

Just need to power the relays by hooking up the yellow wires to 12V and grounding the gray wires.

t_l75 · 12-13-2012, 08:02 PM

Okay great! Thank you all so much!!!! Now the question is, where is the easiest place to wire the yellow wires into the ignition 12V? I can do this in the morning, and then if all is well then that means we are good to go! Thank you once again for the help!

C5 Dude · 12-13-2012, 08:14 PM

Quote:

Originally Posted by blckslvr79

Just need to power the relays by hooking up the yellow wires to 12V and grounding the gray wires.

You have to energize the relays while holding the gray wires on a ground and if everything else is hooked up right the fans should come on.

Also I had a friend that hooked this type of relay kit up on his and he had everything right and they still didn't work. So I get there and yes it's all correct, but I found that he had unhooked and plugged it in so many times that the actual connectors that energized the relay werent making contact. I just squezed them a bit,, plugged them back in and whala, fans came on. So you may have to use a pick and get the female connectors out of the harness to make sure they have not opened up too much.

Good luck.

iburke · 12-13-2012, 09:03 PM

Thats about the screwiest schematic I have seen It wont work like that...

It looks like the relays should be wired to provide power to the fans when the ignition is on and temp is reached providing a ground back from the thermo-switch wire to energize the relay.

But it is not shown to be wired like that. This looks like it was translated in china and never proof read to insure its accuracy.

You have all the parts you need to make it work, you just have to wire it correctly.

The yellow and Grey wires should run to the relay coils. The red wire from the circuit breaker should run to the center contact of the relay, and the purple from the fan should be connected to the normally open contact of the relay.

Now when the thermostat sends ground back the relay will close and the fan will come on.