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Fan mod question.....

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Old 05-31-02, 06:31 PM
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Lightbulb Fan mod question.....

Ok, I was doing this test for the fan mod:

However, there is a way to test the circuitry, (and that leads to a way to make a fan timer). There is a single black wire (with connector) coming out of the ECU that is not attached to anything. To test the fans you need to attach this wire to ground for two minutes while the car is running. With the wire still grounded, turn the car off and the fans will stay on. After 30 seconds, un-ground the wire and the fans switch to low speed. The fans stay on for ten minutes.

The ECU is down in the passenger side foot well. You need to pop off the door sill trim and then pop up and remove all the fasteners holding the foot well panel. Best to go slow with this as the plastic stuff will crack easily. Once the panel is removed you can see the ECU mounted to the chassis. The test lead on mine was just hanging there, toward the front, but I remember someone saying they had to remove the ECU from its mount to get it. The lead is black and has a female spade connector on it. You should test the circuit first to be sure it works. I used a male spade connector end and an alligator clip test wire. Connect it to ground for a little more than 2 minutes while the car is running. Turn the car all the way off and the fans should be running. After 30 seconds disconnect the wire from ground and the fans should switch to low speed and stay on for 10 minutes (it's timed not temp controlled).
When I turned the car off, the fans did not come on. When I grounded the wire, I could hear what sounded like the relays clicking, but no fans.

The wire on my car was Black/Yellow. My question is, is that the correct wire and if so does that mean the recall was done incorrectly?

Any help would be greatly appreciated...
Old 05-31-02, 07:03 PM
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Fan Mod

Sounds like you have the right wire. For the mod to work you have ground the wire and then turn the key on to the ignition position (not the start position) 2 clicks on the key switch. Leave it on for two minutes and the fans should come on. they will run at different speeds depending on electrical load. If you unground the wire and turn the switch off they should stop running....if you want them to run for tem minutes then you need to leave the wire grounded for 30 seconds after you turn the key off . Hope this helps, Jack
Old 05-31-02, 07:12 PM
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Re: Fan Mod

Originally posted by CantGoStraight
Sounds like you have the right wire. For the mod to work you have ground the wire and then turn the key on to the ignition position (not the start position) 2 clicks on the key switch. Leave it on for two minutes and the fans should come on. they will run at different speeds depending on electrical load. If you unground the wire and turn the switch off they should stop running....if you want them to run for tem minutes then you need to leave the wire grounded for 30 seconds after you turn the key off . Hope this helps, Jack
I actually ran the car for 3-4 minutes with the wire grounded, shut the car off with the wire still grounded and no fans.

The fans never came on...

After that, I ungrounded the wire with the car off and touch it to ground it and I can hear a "click"which I assume is the fan relays being switched. Still no fans..
Old 05-31-02, 07:29 PM
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Thats strange....with that wire grounded and the ignition on for 2 minutes the fans should come on even if you didn't start the engine. (all the ignitions lights have to come on) I.E. ABS, check engine, the lights that come on just before you actually start the car. I'm thinking the fan recal may not have been done on your car ? ? ? Not sure. I have two of these cars and they both work that way. the only difference is my MB one stays at one speed. Jack
Old 05-31-02, 07:32 PM
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Originally posted by CantGoStraight
Thats strange....with that wire grounded and the ignition on for 2 minutes the fans should come on even if you didn't start the engine. (all the ignitions lights have to come on) I.E. ABS, check engine, the lights that come on just before you actually start the car. I'm thinking the fan recal may not have been done on your car ? ? ? Not sure. I have two of these cars and they both work that way. the only difference is my MB one stays at one speed. Jack
Ok, thanks for the help. I did check with Mazda a few months way back about my recalls. I'm just guessing the recall was done incorrectly (that wire wouldn't be there if the recall hadn't been done, correct?).

I did wire up the switch already but unfortunately it doesn't nothing at the moment.

I guess I'll bug Mazda next week.
Old 05-31-02, 07:36 PM
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Good luck....it's possible they did it wrong. I believe that wire is there for the mechanics diagnostic even without the recall....not possitive so better check with them. Jack
Old 05-31-02, 11:41 PM
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in some cases, the 221 trip must occur first, before 226 gnd at ecu works, try test with TFA pin in diagnostic plug grounded for low speed fan, ign on. now try same test shoud hear med fan speed for 2 minutes, turn off eng and fan continues, disconnect bot gnds after 20 sec .....?

also check voodo mod at this link:

http://www.scuderiaciriani.com/rx7/fan_mod.html
Old 06-01-02, 12:09 AM
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Originally posted by KevinK2
in some cases, the 221 trip must occur first, before 226 gnd at ecu works, try test with TFA pin in diagnostic plug grounded for low speed fan, ign on. now try same test shoud hear med fan speed for 2 minutes, turn off eng and fan continues, disconnect bot gnds after 20 sec .....?

also check voodo mod at this link:

http://www.scuderiaciriani.com/rx7/fan_mod.html
Actually, grounding that wire has never turned on the fans, not even driving the car around for 30+ minutes or letting it idle for a while.

Like I said, I do hear the clicking sound when grounding that wire, so I'm assuming that it's the relays clicking. Of couse the ECU has turned on the fans itself, but not by grounding that wire.

Thanks, I know I can do the other mod, I'm more concerned about the recall possible not being done correctly.
Old 06-01-02, 11:51 AM
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a little bit off topic, but since this is about the cooling fan, I'm just wondering why does my idle drop down to about 500rpm when the cooling fan comes on, is this normal?
Old 06-01-02, 12:00 PM
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Siayn - It is fairly common, not normal - it means the Electrical Load circuit may not be properly correcting the Idle speed when the fans turn on - Does the Idle go back up if you turn the interior fan switch to position 3 or 4? If not then the EL circuit is not functioningat all.
Old 06-05-02, 01:51 PM
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I did the Dave Disney fan mod and spliced directly into the relays...when the two wires are grounded it turns the fans on...connected it to a switch inside the cockpit and it seems to work...If I flip the swich with the ignigtion on or off the fans come on...

What kinda puzzles me is, I don't know if it ever goes into high speed...NeWay, I don't even know if this help you but thought I would throw something in there...How "post ****" of me
Old 04-09-07, 12:17 PM
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Old post but I wanted to put in some info on the problem. The issue turned out to be the additional harness used for the cooling recall on the '93's. When I had the engine replaced at the dealership many, many moons ago, they used a later year harness. This confused them since the newer harness already had the fan control box connector already on it. They didn't know what to do with connectors other than the ones to the ECU and had things plugged up all wrong.

I noticed this when I pulled the engine out for the rebuild.
Old 04-10-07, 07:03 AM
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So basically your saying you had a double fan recall harness. ? The one that was put in with the 93 recall and then again with the Later model harness and the early model recall harness plugged in to the later harness ? Certainly sounds confusing. Glad you figured out what went wrong. Do the fans work correcly now when that wire is grounded ?
Old 04-10-07, 07:53 AM
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Check that.
With ignition off ground the 3d wire on engine harness yellow connector on ecu(in europe cars is blue white).
If your fan didnt work then you are missing or you have problem with relay extenssion harness who mazda add when install the fan module.
If your fan work when you ground the 3d pin with ignition off then you have problem with fan module (black box) or with your harness.
Maybe engineer who install the new engine harness connect and the little harness of fan module who is connected to the blue x-05 and white x-14 connector near the ecu.You dont need this harness, if you engine harness is new and have the 16 possition black connector.
You need only the control module and the extenssoin harness on relay fans.

Hope I help
Old 04-10-07, 08:17 AM
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Originally Posted by CantGoStraight
So basically your saying you had a double fan recall harness. ? The one that was put in with the 93 recall and then again with the Later model harness and the early model recall harness plugged in to the later harness ? Certainly sounds confusing. Glad you figured out what went wrong. Do the fans work correcly now when that wire is grounded ?
Basically yes, they had a double recall done.

I didn't reground the wire in the new harness as the car is running the Miata Thermoswitch.
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