Parallel Fan Operation

[gabkwong]

Anyone tried this mod to keep the car a little cooler? Do I have to worry over loading the electrical system? Garry has said something like this, but I am not sure this is the correct way to do it. My temp gauge still in the "normal area", but I can use a little more A/C.

http://miata.net/garage/parallel_fan.html

[POS Racing]

When the A/C is on both fans run when the compressor is running, so where is the added benefit?

Plus this bit concerns me :

In this rewiring method the electrical contacts within the Cooling Fan Relay carry and switch the high current inductive electrical loads of two fans while designed to carry the electrical load of only one. Although the relay's reserve design capacity is unknown, it's likely not double as would be required for dependable operation of this critical relay over time. A Cooling Fan Relay failure can result in overheating and total destruction of the car's engine.

[Treibenschnell]

For the reason stated above, I would not do it. Speaking from experience, I can tell you it burned out my relays rather quickly.

[Majik]

On the other hand, I had a relay go out around 4 years ago with normal operation. I wired them together and they have worked flawlessly ever since. (knock on wood)

[trackdog]

Gab,

That is not the way I suggest wiring the fans. On '94-05 you jump the two ground wires on the ECU. Miatas use a ground switching circuit meaning they turn on and off components by breaking the ground wire instead of the hot wire. By jumping the two wires I sent you the information on you are turning on the low current side of the fan relay know as the coil side. This inturn switches the high current side of the fans.

The A/C does not run both fans in all of the earlier year Miatas. Your normal fan setup is the driver side runs based on temperature, usually around 190 deg. The A/C when switched on runs independently the passanger side. If temperature exceeds 230 deg. the ECU will activate both fans.

By attaching this jumper on the ECU you will be activating both fans for all conditions. This is a big improvement and recommend for all Miatas. It will not effect relay life and it does not carry any additional current.

On 90-93 models the ECU does not operate the fans so in that case you must hard wire the two fans together. Still recommended. I would add a seperate relay for this setup.

Here is a link to the wiring schematic for different year models:

www.trackdogracing.com/inst/fan_wiring.pdf

Dawg

[POS Racing]

Hey Gary is there a speed when the fans quit playing a roll in cooling?? Like on the freeway are the fans just along for the ride at that speed??

[trackdog]

It is temperature related so if it is cool enough the fans will not be activated, maybe one day a year here!

Dawg

[SirHustlerEsq]

Yes a cooling system failure can destroy an entire car...if you drive the cylinder head. You'd have to be an absolute moron to let the car get that hot, then keep driving.

I don't know much about these cars, but nothing is stopping you from getting a single pole, single throw relay and using the fan lead as the switch, then pulling power from the fuse box main.

[doc]

Trackdog ,
Sometimes I do get it right the first time sometimes you have to hit me 3-4 times.
On my 96 Miata
What does the oxygen sensor have to do with the wiring of the fans ,do you run a wire from it or something ?
Do you just run a wire from 1A to 1B
Do I run a wire from 3C to 1A and from 3C to 1B
and then do the wires need to be cut loose from the ECU or do they stay hooked to it
Secondly can I run 1 wire from 3C to 1A wrap around it and then take it on down to 1B
A little more explaining would be a big help for me
Thanks

[trackdog]

That's it Doc, no more afternnon martinis for you! The wiring schematic was for our gauge kit which you attach the O2 wire to the ECU and then the gauge. We added the jumper connections to the schematic recommending customers, while you are wiring the O2 to also parallel wire the fans.

Your '96 uses the 1A and 1B terminal connections. Easiest way to wire is to use two vampire connections and about a 4" wire, around 18-20 gauge with the appropriate male connection that stabs into the vampire connection. A simple task for you car since the ECU is behind the seat, but a little bit of a challange for the '99 and up cars. Pull the connections from the ECU will improve access to the wiring.

Test the fan connection by turing on the A/C and see if both fans come on.

Dawg

[TurboDuane]

The A/C does not run both fans in all of the earlier year Miatas. Your normal fan setup is the driver side runs based on temperature, usually around 190 deg. The A/C when switched on runs independently the passanger side. If temperature exceeds 230 deg. the ECU will activate both fans.

While I can't say for all year models, on both my '90 and '97, both fans always came on when the A/C was on. As you said, on the '90-'93 models the fan was controlled by the termometer not the ECU, but on my '97 the ECU is in charge.

[Sharpie]

But if you unplug the wire that controls the compressor, and turn the A/C on both fans will come and keep the compressor to adding extra heat. I had to do this last summer at Hallett. It's a little white plug under the drivers side headlight.

[doc]

Well I made the connection and did the test all seems well,ran the car down the road for a few miles {did carry a can with a lid on it to catch the smoke if something started smoking } did not need it.
Thanks Gary
the plug wires and plugs made a big difference also

[icepenguin66]

On 90-93 models the ECU does not operate the fans so in that case you must hard wire the two fans together. Still recommended. I would add a seperate relay for this setup.

I never heard about needing a stinkin relay for this! I simply cut the wire from the ac fan, that connects the ground circuit (black with blue stripe), and spliced it into the coolant fan's wire (the yellow one). Now when the coolant fan comes on the ac fan does too. Been that way for say 2 yrs now I think and now problems yet...with the fans that is!