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Discussion Starter #1
hi all. i have a 2005 forenza 4L 2.0 auto 2wd 101k. i was at a stoplight when i noticed the temp gauge rising the light turned and i got on the freeway(probably should have turned the car off but i drove home anyway). the temp immediately cooled back to to normal so assumed i had airflow problems. i began diagnosing the problem by testing the fans manually via 12v jumper wires directly to the fan motors. the larger fan spun but the smaller one was bad. i replaced it and started it up. i assumed the smaller fan was for ac and the larger for radiator. the larger fan never seems to come on so i assumed there was a problem and replaced the coolant temp sensor. i still have not seen the larger fan come on(not sure when it should) but the smaller one cycles with the ac and comes on at mid temp with the ac off. the problem now is that the overflow bottle is boiling over at mid temp(according to the gauge) right before or right as the smaller fan is coming on. i need help figuring out what to do next. im thinking possible thermostat failure, bad water pump, clogged radiator or blown head gasket(i see no mikyness in oil nor white smoke in exhaust). i have been driving the car and have been adding water as it boils over just to get me to and from work. since then i have had misfiring (code p0300) i have a limited budget but i am pretty good with a wrench. any help would be appreciated.
 

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hi all. i have a 2005 forenza 4L 2.0 auto 2wd 101k. i was at a stoplight when i noticed the temp gauge rising the light turned and i got on the freeway(probably should have turned the car off but i drove home anyway). the temp immediately cooled back to to normal so assumed i had airflow problems. i began diagnosing the problem by testing the fans manually via 12v jumper wires directly to the fan motors. the larger fan spun but the smaller one was bad. i replaced it and started it up. i assumed the smaller fan was for ac and the larger for radiator. the larger fan never seems to come on so i assumed there was a problem and replaced the coolant temp sensor. i still have not seen the larger fan come on(not sure when it should) but the smaller one cycles with the ac and comes on at mid temp with the ac off. the problem now is that the overflow bottle is boiling over at mid temp(according to the gauge) right before or right as the smaller fan is coming on. i need help figuring out what to do next. im thinking possible thermostat failure, bad water pump, clogged radiator or blown head gasket(i see no mikyness in oil nor white smoke in exhaust). i have been driving the car and have been adding water as it boils over just to get me to and from work. since then i have had misfiring (code p0300) i have a limited budget but i am pretty good with a wrench. any help would be appreciated.
In your engine room fuse and relay block, visually inspect the fuses "COOL FAN LOW 20A" and "COOL FAN HI 30A".
Next you will want to test your COOL FAN LOW and COOL FAN HI relays. Do this by substituting with a known working relay I remove them one at a time and insert them into the PWR WNDW relay socket next to them. If my power windows still work, the relay is good.
If these items check out good, there is a third relay called the Cooling Fan Control Relay. It is located adjacent to the main (large) fan attached to the frame of the car with a bolt. You'll need to test this one with a known good one. I think it's the same pin configuration as the previously mentioned relays, but with a weatherproof cover, but I'm not 100% sure (can't remember). I do know it is possible to splice in your own relay/socket combo. Not easy, but doable. If you wish to go this route, let me know and I'll help post the wiring diagram.
Good luck!
 

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I probably should have posted this info from the manual first :blush:

The cooling fans are mounted behind the radiator in the engine compartment. The electric cooling fans increase
the flow of air across the radiator fins and across the condenser on air condition (A/C)-equipped vehicles. This
helps to speed cooling when the vehicle is at idle or moving at low speeds.

The main fan size is 340 mm (13.4 in.) in diameter with five blades to aid the air flow through the radiator and
the condenser. An electric motor attached to the radiator support drives the fan.

A/C models have two fans-the main fan and the auxiliary fan. The auxiliary fan is 300 mm (11.8 in.) in
diameter. Non-A/C models have only the main fan.

A/C OFF or Non-A/C Model:

- The cooling fans are actuated by the Engine Control Module (ECM) using a low-speed cooling fan relay
and a high-speed cooling fan relay. On A/C-equipped vehicles, a series/parallel cooling fan relay is also
used.
- The ECM will turn the cooling fans ON at low speed when the coolant temperature reaches 93 °C (199 °
F) and at high speed when the coolant temperature reaches 97 °C (207 °F).
- The ECM will change the cooling fans from high speed to low speed at 94 °C (201 °F) and will turn the
cooling fans OFF at 90 °C (194 °F).

A/C ON:

- The ECM will turn the cooling fans on at low speed when the A/C system is ON. The ECM will change
to high speed when the coolant temperature reaches 115 °C (239 °F) or the high side A/C pressure
reaches 1,859 kPa (270 psi).
- The cooling fans will return to low speed when the coolant temperature reaches 113 °C (235 °F) and the
high side A/C pressure reaches 1,449 kPa (210 psi).
 

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Discussion Starter #4 (Edited)
thanks p1nky, i had all ready checked the two relays in the fuse box(forgot to mention that in post) but i was not aware of the third. i will go look for it now. can you be a little more specific about the third relay's location just in case i cant find it?

***edit*** i found the third relay i am heading to a parts store to see if i can test it. it has 5 pins instead of 4 like the others
 

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Discussion Starter #5 (Edited)
i tested the relay it is a 5 pin(the others are 4 pin)
ooooooooo
o30ooo86o
o~ooooo~o
o85o87*o87
o~oo~oo~o

i gave power via 12v jumper to the 85, grounded the 86, clicked as it should. tested the resistance through the 30 to both the 87* and the 87, the 87* circuit was open the 87 was closed i assume the relay is bad?
 

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When you apply power to the relay, you should have continuity between pins 30 and 87 and no continuity between 30 and 87a.
When you remove power, it should have continuity between 30 and 87a and no continuity between 30 and 87.

If it checks out, you need to check the wiring leading to it. Be careful working around this area and keep clear of the fan!

Pin 87 (Black wire) is ground (it is bolted directly to the frame somewhere behind the left headlamp). Check to see if there is ground present.
Pin 85 (Pink/Black wire) should have +12v when the ignition switch is in the RUN position.
Pin 30 (Light Blue) goes directly to a terminal on the main fan (large one). Unplug the fan and check this wire for continuity. The other wire of this fan (also light blue) goes directly to pin 87 of the COOL FAN LO relay.
Pin 87a (Violet wire) goes directly to terminal 2 on the auxiliary fan (small one). Unplug this fan and check for continuity. Terminal 1 of this fan goes directly to chassis ground.
Lastly, pin 86 (Gray wire) carries the ground signal from the ECM which makes the Hi/Low switching possible. It connects to a Blue wire which then connects to pin E34 on the ECM and pin 85 on the COOL FAN HI relay.

I'll try to make the schematic available, but I'm currently having trouble with my PDF reader.
 

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Discussion Starter #7
Lastly, pin 86 (Gray wire) carries the ground signal from the ECM which makes the Hi/Low switching possible. It connects to a Blue wire which then connects to pin E34 on the ECM and pin 85 on the COOL FAN HI relay.

you lost me at this step.
everything else checks out, relay good, and continuity was good until the last step, i tried testing continuity between pin 86(grey) and 85 on the cool fan hi relay but got none i couldnt reach the ecm so i will access it and wait on your response. thanks again
 

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***correction***

Me - "Lastly, pin 86 (Gray wire) carries the ground signal from the ECM which makes the Hi/Low switching possible. It connects to a Blue wire which then connects to pin E34 on the ECM and pin 85 on the COOL FAN HI relay."

You - "you lost me at this step."

No wonder I lost you; That last bit of info is partially incorrect. I pulled it off the schematic I had, which was for the '07 Forenza, and it seems the ECM pinout differs. The correct pin should be K12, Dark Blue wire and is designated (on the schematic you found, which is the correct one) High Speed Cooling Fan Relay Control.

So, according to this schematic;

Pin 86 (Gray wire) of the COOLING FAN CONTROL RELAY goes directly to pin 10 of connector C113 (black 16 pin square connector Behind ECM Bracket).

Then it connects via another gray wire to pin 24 of connector C108 (black 24 pin rectangular connector at the Left Engine Fuse Block).

After this connector it becomes (or is spliced to) 2 Dark Blue wires.

One goes to pin 5 of connector C106 (white 20 pin rectangular connector at the Engine Fuse Block) and further to pin 85 on the COOL FAN HI RELAY.

The other Blue Wire goes directly to pin K12 on the ECM.

Under the schematic you will find the connector information, along with their pinouts.
Sorry for the late response and the confusion. I will edit the original post to reflect the error.

***edit*** cannot edit previous post. I hope readers will refer here for the corrected version.
 

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Discussion Starter #10
ok that wiring diagram helped, checked the continuity, it was good. studied the wiring diagram and decided to give the ECM k28 pin(from the wiring harness) 12v manually, both fans came on. i guess the next step is finding out why the ECM is not telling the fans to come on?
 

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I hope you mean you grounded the ECM k28 pin, not gave it +12V !
That would be bad for the ECM.
Once you let out its "magic smoke", there's no putting it back in! ;)

If you ground pin k28 (Green/White), both fans should run at low speed (fans are configured in series with one another, so the 12v is divided between them).
If you ground pin k12 (Blue) both fans should run at high speed (fans are now in parallel and get a full 12v each).

If both tests pass, and you don't have any trouble codes, it is either the temperature sensor or the ECM which is faulty. If the ECM is suspect, I'd take it to a shop or the stealership.
 

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Discussion Starter #12 (Edited)
i see my mistake now, i should have grounded the k28 with the ignition on. what i did was give 12v to the k12 on the wiring harness(disconnected from the ecm, i didn't let out the magic smoke) to the 85 on the cooling fan low relay, which switched the relay letting the 87 have current from the 30. this turned both the fans on low speed. so am i safe to assume that the ecm is at fault?
 

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Suspect ECM 06 Forenza

I've been researching the same problem. Only the big fan runs, and only if the AC switch is on, otherwise it overheats. Little fan works fine electrically, and voltage is available at the connector, but the ground side, which appears to be the ECM, reads about 400k Ohms - with the engine running and hot enough to make the big fan cycle. I don't think it's getting the discreet signal.
All relays check good, temp sensor too. An oddity with this is the "finely crafted EGR adapter" has another temp sensor (located right next to the big temp sensor) without any connection. Scratching my head, the gasket kit did not contain the proper gasket for it either, even though it was specific to this car. "Exact fit". $4.50 turned into $85 if you wanted the 20 cent O ring as part of the installation (check Ebay!). Fortunately I have a large stock of O rings and managed to have a -314.
My daughter called me to come get it after she couldn't get it started anymore...
Blown head gasket, no brakes, one destroyed rim and tire, and not a drop of oil.
Believe me folks don't use plain water in an engine with aluminum heads!
Barely enough meat left to bolt it back up (after resurfacing).
ECM? What do you thing?
 

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im kinda having somewhat of the same issue, both of my cooling fans will not work. ive manually tested them and they do work, ive checked fuses and grounds and still nothing. another strange thing is that only on my passenger side my blinker works fast. i checked and changed the bulbs on that side and i checked the ground, for some reason my light on that side from my headlight is dimmer than the other side.. any and all ideas are welcomed!!
 
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