SPAL Fan Wiring (Basic Wiring Assistance)

[Fresh1179]

Hey Guys,
I’m looking for some assistance with some wiring a SPAL fan for my new radiator. I will readily admit my wiring knowledge is limited. There are plenty of examples of wiring with the Mishimoto harness and with deletion of the Aux fan. I am going to retain the Aux fan and I don’t have a Mishimoto harness so I was hoping to run some questions by y’all before I start soldering.

1. I am not confident in my placement of the 12 VDC line. I have it connected to the positive terminal in the engine bay, but I’m not sure this supply’s 12 VDC....

2. Ignition Source-I am not quite sure where to attach this too. I have seen the flashlight and accessory lights (glovebox) as switched ignition sources. Would these be correct?

I have drawn a crude picture of my (probably) wrong diagram.





Any help is greatly appreciated!


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[WOLFN8TR]

Everything looks good on your wiring diagram. The Orange wire is basically a signal wire to turn on the relay so it has a very low amp draw. I personally installed a fuse on both positive lines to be safe. Use a 15/20amp on the line to the Red/Yellow ignition wire and the 30amp ( that came with the relay ) on the Yellow line from the relay to the Postive lug in the engine bay. Hope this helps...

Yellow: Postive Lug
Orange: Red/Yellow Stripes

[bigjae46]

Everything looks good on your wiring diagram. The Orange wire is basically a signal wire to turn on the relay so it has a very low amp draw. I personally installed a fuse on both positive lines to be safe. Use a 15/20amp on the line to the Red/Yellow ignition wire and the 30amp ( that came with the relay ) on the Yellow line from the relay to the Postive lug in the engine bay. Hope this helps...

Yellow: Postive Lug
Orange: Red/Yellow Stripes

The diagram shows a negative trigger so only need to put a fuse on lead 30 from the relay to the battery and the positive lead of the fan.

Relays should be wired with a ground trigger for safety and less wiring.


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[WOLFN8TR]

The sensor is the Negative trigger for the fan.

The Ignition wire powers the relay initially. When the sensor calls for cooling the negative trigger is activated and power flows thru the relay from the direct battery connection to the fan.

In your opinion where does the ignition wire go?

[bigjae46]

Connect 30 to ground and 87 to the negative lead on the fan. Connect fan to +12v.

When the ignition switches on, the relay closes and provides a ground to the fan and it will run. Remember DC flows from negative to positive.

This is different from wiring a car stereo system...your diagram is how you would typically wire control circuits to turn on components.


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[Casa de Mesa]

The sensor is the Negative trigger for the fan.

The Ignition wire powers the relay initially. When the sensor calls for cooling the negative trigger is activated and power flows thru the relay from the direct battery connection to the fan.

In your opinion where does the ignition wire go?

Is this drawing to scale? 😁

Wise ass comments aside, this is super helpful. Appreciate you posting this for the OP and others.

[bigjae46]

The sensor is the Negative trigger for the fan.

The Ignition wire powers the relay initially. When the sensor calls for cooling the negative trigger is activated and power flows thru the relay from the direct battery connection to the fan.

In your opinion where does the ignition wire go?

On other note.

85 and 86 power the coil. So that needs a power and ground.

30 and 87/87a are a contact. So 30 completes a circuit with 87 when the coil is powered and then completes a circuit with 87a when the coil is not powered.

The only +12 that gets fed into the relay is 85 or 86 which should be fused.

Then the other lead on the coil (85 or 86) is to ground. On the coil ground, you can wire a switch, sensor or some other control module.


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[Kcalhoun27]

This isnt what youre asking specifically, but i wired mine directly to the aux fan and then removed the factory mech and aux fans. Ive never had an issue with it. I do not track my car and i live in delaware where it isnt particularly hot. But this solution has worked for me

[Fresh1179]

Quick question. My temp sender has two wires marked 0 and 1. I am assuming that these are two separate wires for the fan switch, and a secondary for data logging. Any thoughts? I’m trying to button everything up before filling everything back up.



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[Fresh1179]

Anybody on the above?


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[Fresh1179]

Alright. So I am confounded.

I replaced my entire cooling system.

Fan: I simply cannot get the fan to turn on. I checked that the fan functions by just connecting the positive and negative to a spare battery. Currently, I have the 12 Volt Power (Red) attached to the 12 volt on the relay with a 30 amp fuse. The fuse is seated and not blown. The negative on the fan is connected to the black lug in the "drug bin". The power coming from the fan is connected to the the yellow on the relay. The ignition is wired to the the wire located in the pictures above. The grey sending unit is connected to the the green wire (I have tried both wires). The fan will not power on.

[WOLFN8TR]

It looks like you reversed the Yellow and Red connections from the Relay. The wiring diagram shows the following.

Relay RED: To Red Fan Wire
Relay Yellow: To + Post Engine Bay (Fused)
Orange: To Ignition Wire

On the wiring diagram it shows one "Grey" wire that goes to the temp sensor, which looks like it's a single wire sensor with a lug connection. What's up with the sensor with two Green wires? Once you correct the wiring connections above see if the fan comes ON if not switch the Grey wire to the other Green wire.

[bigjae46]

Some switches ground through the body of the switch assuming it screws into a bung that is a common ground.

I’d guess the switch you have would have one lead that you connect to ground and the other that goes to your relay. You can confirm with a multimeter.

There is no point in having a multi-output switch. It’s not resistance based like a temp sender.


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[duracellttu]

To ensure your SPAL relay is wired correctly, removed the grey wire from the sensor and connect it to ground, then start the engine (not position 1 or 2 with the key, turn the engine over). The fan should turn on immediately. If it doesn’t, check the relay wiring again.

The grey SPAL relay trigger is ground activated, which means not all temps sensors will work with it. For example, the OEM temp sensor can’t be used to trigger the SPAL relay. This is why SPAL recommends using their temps sensor. The only problem with using the SPAL temp sensor is that the size/threading doesn’t fit most radiator or radiator hose bungs. For this reason, lots of members will remove the AUX fan and splice into the AUX fan relay to power the SPAL fan.

[Fresh1179]

I agree. I wish I just had the normal sender that SPAL makes, I even purchased one but it did not fit the threading of my radiator (Zionsville) so I could not use it. It was the correct size, but the non-threaded portion was too thick to enter the radiator if that makes sense. The probe that was supplied with my radiator has a thinner probe section w/ correct threading. The pigtail with the green wires was supplied with the unit so I am hoping that it works as intended. My only thought is that they maybe used it for double fans where multiple relays are required. Regardless, anything that complicates wiring for me, as you can probably tell, is not a good thing.

It does appear that I did not wire the yellow and red correctly. The damn wires have “fan positive” on the yellow and “12 VDC” on the yellow. I am 99% certain on that. Regardless, I ordered another relay that I will “dry fit” to make sure everything has is going to work per the suggestions and let y’all know. I appreciate the help.


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