[Danny T]

Hi folks,

I know this has been asked many times before but the search isn't netting me any results.

I removed my twin flexalites and opted to go with 2 zirgos. The way I had the flexalites installed was to turn on via thermostat switch. The problem with this is that I cannot run my A/C because the fans only come on at certain intervals (activated via separate temp sensor I installed in my lower rad hose). I do not want to wire the fans to stay on 100% of the time so that option is not the way i want to go (unless I have to).

So Question # 1

Is there a way to wire the fans the same way I had before but to add a trigger/wire to turn/keep the fans on when the AC is turned on? And where would I find this wire/trigger source?

Question #2

Is it recommended to use 2 separate relays (1 for each fan) or can I just wire them up to run off of 1 relay only?

Thx.

Danny

 

[1A1]

You have a few options. Yes you can run them so that they can come on in 2 ways-one way with a thermostatic switch and another with a switch that you can control from the cabin. No problem. Simply run 2 power supplies to the fans. 1 will come from the thermo switch. The other from the cabin.

Another option is to go with the SPAL pusher fan from MVP. I believe Dusty sells a nice skinny 13 inch fan, which actually replaces the stock pusher fan on auto cars when people install front mounts. This will help to cool the condenser.

Steve K.

 

[Ishii]

Fun with Relays

Disclaimer: I (the submitter) am not ressponsible for any missunderstanding or misshaps due to the attached wiring diagram. Use at your own risk and only if you understand it!


Ok, the truely simply complicated way to wire 2 aftermarket fans is in the wiring diagram that I made attached below.


What it Does:
It will run the fans in a parrallel (high speed) or a Series (Low speed) circuit.

If the A/C is switched on, the signal for the magnetic clutch will turn on Radiator fan Relay #3 causing the fans to run at low speed in a series circuit.

If the A/C refrigerant pressure rises higher than normal, the A/C single pressure switch will turn off causing Radiator Fan Relays #1 and #2 to switch to normal off position causing the Fans to run at High Speed in a parallel circuit.

If the Engine Coolant Temp Switch (water temp switch) should open due to high coolant temp. The fans will operate at High Speed

The Additional "Manual Switch" is also wired in series with the A/C single pressure Switch and Engine Coolant temp switch. So, by manually opening this switch, you will turn both fans on at high speed. (be sure to wire this switch closest to the relay in series)



I'm sure you clever guys will realize that most of the components are already in the car and you will only have to add a Radiator Fan #3 relay, 30amp fuse and a manual switch. (and of course a bunch of rewiring)

I'm sure if you study this diagram you will be able to see there are alot of possibilities with this wiring modification. So I'll leave it up to you how you make this circuit. But I would reccomend, adding a lower temperature switch in series with the other switches, so in order from closest to the relay #1 it would be.....
Manual switch, Aftermarket lower temp engine coolant temp switch, A/C single pressure switch, Engine coolant temp switch(factory)





This diagram was drawn using a Toyota style wiring diagram. Meaning it is drawn as if there is no power on any part of it. (normally off)
It also happens to be the same way toyota operates their electric fans on many other models. But I have taken a Supra wiring diagram and moddified and also added in a manual switch.

be especially careful to note the normally off positions of the relays!!!



Ishii

This is how you will have to make your wiring, please refer to the original wiring diagram to see what has changed (so you will know what to add)

 

[Danny T]

Thanks guys !!!!

Danny

 

[kazumaTRD]

Great write up and pix to go with it. Thank you. I will be buying a dual fan kit and was wondering how best to rewire it. but will first need to look into the manual to get going.

 

[kazumaTRD]

Followed the schematic ... completed it, FAN is on high speed constantly, even without key into ignition! , double checked all rewiring, still on, key in, still on, had a on/off switch... still No good, I have rewired back to stock and will figure out another way of doing this. perhaps someone else can chime in.

 

[kazumaTRD]

anyone else have a way to rewire dual electric fans.

 

[Ishii]

Followed the schematic ... completed it, FAN is on high speed constantly, even without key into ignition! , double checked all rewiring, still on, key in, still on, had a on/off switch... still No good, I have rewired back to stock and will figure out another way of doing this. perhaps someone else can chime in.

I think you missed the part in the schematic that says "From Power source only on with Ignition on"

And if the A/C single pressure switch or the Engine coolant temp switch is "open" the fans will run at high speed, its the same thing as opening the "on/off" switch in my diagram.

But if your engine was cold and the A/C wasn't at high pressure and the Fans were running at high speed, then I'd assume the wiring wasn't done correctly OR perhaps you have a problem with the A/C single pressure switch or the Engine coolant temp switch. Check to see if you get a "Relay switch ground" at Radiator fan relays #1 and #2 with the relays unplugged. If no ground is present and you know that both the engine coolant temp switch and A/C single pressure switch should be closed, then you better figure out where the problem is with that part of the circuit.
Maybe you didn't plug the Engine coolant temp switch in (on the radiator)

Also with the key on, you need to have current flowing from the HTR fuse to the coils of fan relays #1 and #2. otherwise the fans will be running.

The on/off switch for this cicuit doesn't mean exactly "on" or "off" only. By opening the on/off switch will turn the fans on at high speed. But if the A/C single pressure switch opens or the Engine Coolant temp switch opens the the fans will run at high speed. That is the beauty of this circuit. It will automatically do as it needs incase you forget or arn't there!


Let me know if you have any questions here not by PM.

Ishii

 

[Ishii]

I think you missed the part in the schematic that says "From Power source only on with Ignition on"

Ishii

Let me further explain this one. From this diagram if power (+ voltage) is comming from the Fan fuses and NOT the HTR fuse, then the fans will be running at high speed. That is how this circuit works. Thats why power should only be applied to those fuses with the ignition "on".

Follow the diagram: Power is flowing from the 30a fuse on the right, it runs down the Blue with black stripe wire through the A/C condensor fan motor into the brown wire into the Radiator Fan Relay #2 then to ground via the white with black stipe wire. MAKING THE FAN RUN

At the same time:

Power flows from 30a fan fuse on the left down the red wire, into Radiator fan Relay #1 down the Blue with Black stipe wire into Radiator fan motor and then down the White with Black stripe wire to ground. MAKING THE FAN RUN


Next operation:

If Power is applied to the HTR fuse to the coil of Radiator fan Relay #1 and #2 and the negative side of the coil of Relay #1 and #2 has ground flowing "from ground through the engine coolant temp switch, through the A/C single pressure switch and through the on/off swithc to the relays, THEN
Power flows from the 30a fan fuse on the right down the Blue with black stripe wire through the A/C condensor fan motor into the brown wire into the Radiator Fan Relay #2 then through the Blue wire going to Radiator Fan Relay #3. THE FANS WILL BE OFF IN THIS CONDITION.

BUT!!! if current is input from the AC magnetic clutch relay to the coil of Radiator fan relay #3 then the power will continue to flow through Radiator fan Relay #3 to the radiator fan motor to ground making a SERIES circuit and the fans will run at LOW speed.
NOTE: In this condition Radiator fan relay number one will be "on" opening the connection between the left 30A fuse (red wire) to the radiator fan motor. This prevents the circuit from shorting directly to ground.

Next operation. If any of the followin opens
On/off switch
A/C single pressure switch
Engine coolant temp switch
Then the relays will revert back to their normally off condition. That will make the power flow as first described making the fans run in a parallel High speed.

Make sense?

Ishii

 

[kazumaTRD]

I had taken the power from the relay #2 pin2 and just switched into relay #1 pin2, since it seemed easier and not realizing it needed to be a swiched (ignition on) power source, this is were I must have went wrong. thx, I will redo with correct power source.

 

[Ishii]

Here follow the arrows

 

[MKIV93Supra]

Does anyone have pics of the diagrams that were made? They appear to be missing in this thread now