Wiring my fans. I'm a n00b

[4g63tcrazy]

Yeah I've searched for a few days on and off and cant really grasp this concept. I feel like I am just having a brain ****. I can rewire my whole engine harness but I can't wire up my fans..

Basically I will be running 2 fans. 1 pusher and 1 puller. I would like to wire them both to come on at the same time by a switch inside the car, with a relay that I will control. Can someone just give me a quick paint drawing of where the wires need to go off the relay? Or do I not even need a relay?

I've read other ways of using the a/c relay but I got rid of that fuse box and I don't like how late my car turns the fans on right now. I also plan on having link turn the check engine light on once temps start climbing so I can't ever forget.

I have another idea. Couldn't I leave the fans wired up to the stock plug but tap into the power wire with the switch so the car will still have control over it, but whenever I feel the need to I could go ahead and turn them on?

[LingLing]

I think you can just tap the power from either a switched or constant power source then run a basic switch between both the power and ground wires.

I would definitely double and triple check my advice, but that's how I wired up my fans on my Integra when the relay stopped kicking them on automatically.

[4g63tcrazy]

That would work if I did not have to use a relay. Just run a power wire to the fans and run a switch into that wire. Just curious if I would need a relay or not. Or if I could leave it hooked up like stock and still run a switch for whenever I felt I wanted to turn them on.

[blackrosenova400]

If you run a switch and no thermostatic switch you would be ok. If you run the thermostatic switch you need to run a relay as the thermostatic switch cannot take the load.

[4g63tcrazy]

Ok so if I wanted to tap into the stock wiring and run a switch to it I would need to use a relay?

Here are some paint drawings I came up with.

Switch only:


Tapping into stock wiring:


Can someone add how I would run a relay into the second one?

[Alpha D]

You beat me to the drawing. Mine basically is the same idea. Adding the relay makes it complicated i think. Since you will be using the small current to control the large one. I think battery power and a ground should work just fine. With like a inline safety fuse or something.

[Alpha D]

I remember when i was talking to swifty he mentioned wiring his own fans shoot him a pm. Im sure he will help.

[123abc]

All I've ever done is run a wire from the + to the switch, then from the switch to the + on the fan wiring and of course grounding out the fan. I would wire the fans in parallel since you're doing two though.

[blackrosenova400]

Here ya go with a thermo switch

[Alpha D]

^^ Now that brings back BAD MEMORY'S (electrical class) Very simple to understand. Thank you very much nova. My question, your gonna have battery voltage magnetizing the coil to pull the armature shut? So then only when the thermistor gets warm enough closing the contact points and then allowing the current to find a way to ground switching the fans on?

[s1ngletracker]

dude, everything in that box is a relay. I just recently did something like this with my jeep, and that is an apropriate way to do it. Just make sure the relay is rated for the (combined) amperage draw of the fans. I don't think you wanna just have your fans wired to a switch. Too much potential for 'human error'. You could wire up a manual override/disable though. I did that with a SPDT switch. DPDT would be even better.

[4g63tcrazy]

Originally Posted by blackrosenova400

Here ya go with a thermo switch

So I would put the switch in the wire going from the positive battery terminal to the #35 on the relay then right? Now I need to figure out which wire is positive and which is negitive coming from the thermo switch.

[Pushit2.0]

The only thing in the diagram I see is I would have switch power from the relay going to the fans, not switched ground. They will work either way. The thermal switch does not have a positive/negative, when it gets above the set temp it completes the circuit between the terminals. And in this case it would complete the ground circuit on the trigger side of the relay to complete the ground circuit of the fans so they turn on. Also if you want one fan to be a pusher and the other fan to be a puller you will have to have the polarity switched going into the fans, so if your wires are blue and black coming out of the fans you will have a blue and black from each fan be positive and the other blue/black wires as ground. Also with the relay you would have 30 as your main fused power from the battery, then 87 out would go to the fans, and 87a is not used. Then have 85 as your switched power 12v, not straight from the battery, and have 86 go threw the thermal switch to complete your circuit to ground, you could use any good chassis ground to avoid extra wire length.

~John

[blackrosenova400]

You would add a switch to bridge the thermostatic switch. I added arrows pointing to the wires to use.

[4g63tcrazy]

Originally Posted by Pushit2.0

The only thing in the diagram I see is I would have switch power from the relay going to the fans, not switched ground. They will work either way. The thermal switch does not have a positive/negative, when it gets above the set temp it completes the circuit between the terminals. And in this case it would complete the ground circuit on the trigger side of the relay to complete the ground circuit of the fans so they turn on. Also if you want one fan to be a pusher and the other fan to be a puller you will have to have the polarity switched going into the fans, so if your wires are blue and black coming out of the fans you will have a blue and black from each fan be positive and the other blue/black wires as ground. Also with the relay you would have 30 as your main fused power from the battery, then 87 out would go to the fans, and 87a is not used. Then have 85 as your switched power 12v, not straight from the battery, and have 86 go threw the thermal switch to complete your circuit to ground, you could use any good chassis ground to avoid extra wire length.

~John

Instead of switching the polarity I was just gonna take the fan blades off and flip it around. But either way would work..

Originally Posted by blackrosenova400

You would add a switch to bridge the thermostatic switch. I added arrows pointing to the wires to use.

How exactly would I use a switch to bridge the thermo switch? I understand now that when it gets to a certain temp the thermo switch connects the circuit. So with the switch I would need to be able to flip it on and connect it. Do I need a 2 pronge switch? 3 pronge?

I feel like I'm not understanding the most simple concept and it's throwing me for a loop..

[4g63tcrazy]

Ok so I think I got it. This one is switched power instead of ground. Let me know if I'm missing anything.

[blackrosenova400]

Thats perfect

[4g63tcrazy]

So basically this is how the car is wired up stock and all I need to do is put a switch between the 2 wires coming off the thermoswitch? Or is it wired in a different way?

[goodhart]

Ugh, wiring makes my brain hurt...

[LingLing]

Originally Posted by goodhart

Ugh, wiring makes my brain hurt...

+1 I'm with you there. I hate wiring with a passion.