electric fan, wiring check, on/off/on, therm

Hello I am new to the forum and all the information was found while researching on how to make my electric fans run. My car is a sc300 with a 2jzgte (if it matters) and the fans are from a 2003 is300.
I come here to ask if anyone has suggestions or changes that need to be make to the diagram. My main concern is on the switch itself (in green) the switch came with the diagram noted. Thanks


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Sc300 - 2jzgte

If I'm reading your diagram correctly when that thermal switch closes, it is just going to short your switch out. I'll try to get a correct diagram together tonight. Do you know what amperage each fan pulls?

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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205

Here is a very crude diagram... but it should give you the idea.


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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205

Hey thank you so much.
To make the digram you gave me gives me either three options. On for always on, Off in the center, And auto the ones that goes to the thermal fan switch?
Also does it matter if 86 is ground vs. 85 being a ground?

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Sc300 - 2jzgte

Yes, the switch should have an input, then a contact for on and for auto. With the above diagram if the switch is on, the fans will be one. If the switch is set to auto it will use the thermal switch to turn them on.

I have never had any issues with which pin (85/86) goes to positive vs ground. I've connected it both ways without an issue.

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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205

Thank you so much good sir. 100 internets

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Sc300 - 2jzgte

If you want the fans to automatically shut off with the car then take the input for the switch off an ignition source instead of a 12v constant source.

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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205

Kenny, ignition to a relay, at least 80 amps switching required, the onrush if both cut in at once can be 80 amps +.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Maybe I was unclear. I meant to ONLY run the ignition input to the switch... which in turn runs the relays. DO NOT run the ignition to the input of the relays because it will blow your ignition fuse (more than likely).

I was not aware those fans pulled that much amperage. Check the rated draw and if Howie is correct (and he usually is... lol) make sure to get adequate relays to handle the draw.

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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205

Ok I will check that as well.
Are you sure that the thermostatic switch is correct? Iv been doing alot more searching and it seems that the switch has two terminals one that goes to a 12v source and one that connects to ground. ?

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Sc300 - 2jzgte

something like this here ..https://www.ramchargercentral.com/electrical/electric-fan-wiring/

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Sc300 - 2jzgte

That diagram there is just using the thermal switch on the ground instead of the power. I wouldn't recommend connecting it like that because you will be getting the full draw of the fans through that switch. If it is not meant to handle that much current it will burn out. Wiring it like I posted will draw very minimal power from both the manual switch and the thermal switch.

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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205

X 2 with what offroadzj said. If it has two wires and becomes a closed circuit, i.e. a switch, pos to neg or vice versa = BANG.
You can switch pos to pos or neg to neg.
All modern vehicles use low current often negative switching, think of a defroster.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Thank you guys for your input.

I dont really need the fans to turn off with the car because I will be running a turbo timer and according to a lot of people the temp usually comes down when the car is standing still with both fans on.

hat gauge wire and what kind of relays would be sufficient enough for the fans. I tried to look for draw but couldnt find it anywhere.


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Sc300 - 2jzgte

Promise this will be the last diagram but Im a visual learner. Does the indiacter light seem right, just so i know that the fans are on by choice?


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Sc300 - 2jzgte

No that will stay on all of the time!
You need it on the centre tap, next one down but that will simply tell you there's power going to the fans. It won't actually tell you they are working.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Yes, what he said.. haha. how you have it now will keep the light on all the time. If you really want to have the best case scenerio then you will want to tie the LED into the power to the fans after the relays. This way if the relays ever went bad you would know... because the fans would no longer get power and the LED would not illuminate. That would be your safest means. But still, if the fans went bad, then there would be nothing telling you.

Being that you will have it on a turbo timer then you probably do want to run the fans off the ignition. Otherwise you are defeating the entire purpose of the turbo timer. If you run if off constant power then the only control of it will be by the switch. So if you leave the switch on when you get out and set the turbo timer, the fans would just stay on... or you would have to wait in the car til the turbo timer turned off and then turn the switch off. By connecting it to the ignition, you can leave the switch on and then when the turbo timer shuts down (and kills the power to the ignition) the fans will automatically turn off.

The absolute best case scenerio would be to hardwire constant power through the thermal switch to the fan relays and then have just a simple on/off switch to be able to manually turn it on. This way you would always have a protection and the fans would kick on automatically whenever they needed to. Otherwise you may accidentally forget to turn the fan on and cause damage to the motor... I almost did this on a Jeep I had. I wired the fans to only come on by the switch and didn't realize that someone had turned it off on me one day and the engine overheated. Luckily it didn't cause any damage, but it could have been a really bad day.

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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205

O ok. If you can pleeease do me the favor and redoing the last diagram woth a simple on off switch ? I tried but I couldnt make sense of it.
Thanks

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Sc300 - 2jzgte

Here is a diagram with a constantly wired thermal switch and a manual on/off switch. To get it to turn on/off with the ignition, connect the toggle switch input to an ignition source (fuse box, ignition switch, etc). You can leave the input to the thermal switch to constant power so it continues to run until the temperature drops below the switch value.



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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205

Thank you so much and for putting up with me.
Do I find a simple heavy duty Toggle switch to wire this up?
Also would I need 40amp relays for this setup would compensate?


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Sc300 - 2jzgte

You won't need a "heavy duty" switch you're only switching relay coils max draw, 3 amps.
What's the on rush draw (switching on current draw) of each fan, add about 5 amps to each, that becomes your fuse and relay rating, either one fuse X twice that rating as per the diagram above or two feed lines and fuses, one for each relay, IMO safer.
P.S. From your questions here, I would suggest you follow that diagram slavishly.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

. I had the fans wired up before with relays but I did not have an over ride switch to them.

Thank you so much for you input!

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Sc300 - 2jzgte

The override switch should switch the relay(s), not the fan power. It just needs a few diodes (IN4004 etc) and a low-power switch.