What Relays Controls radiator fan operation? GLi 96 corolla

**gabygab** · April 9th, 2013 01:47 PM

1. When the aircon is off radiator fan is not turning ON at 80 degrees but turns on at 80 when AC is on.
2. Sometimes aircon fan do not operate when aircon is on upon turning on aircon. IBinunot ko fan terminal and tested the terminal it has voltage 12-13V at terminal, is my fan defective? but sometime it runs. I already tested the fan connecting it directly to the battery and it operates.

TIA

**jick.cejoco** · April 9th, 2013 03:14 PM

Originally Posted by gabygab

1. When the aircon is off radiator fan is not turning ON at 80 degrees but turns on at 80 when AC is on.
2. Sometimes aircon fan do not operate when aircon is on upon turning on aircon. IBinunot ko fan terminal and tested the terminal it has voltage 12-13V at terminal, is my fan defective? but sometime it runs. I already tested the fan connecting it directly to the battery and it operates.

TIA

ang gulo ng post.
there are two fans for corolla, one is radiator fan and the other is a condenser fan.
when the engine coolant is still cold and the aircon is on, both radiator fan and condenser fan runs at half speed
when the coolant is around 90 degrees celsius and the a/c is off, the radiator fan runs at full speed and the condenser fan stays off
when the coolant is hot and the airconditioner is on, both radiator and condenser fan run at full speed.
with your description, check the condenser fan relay, it is marked CDS on the relay box legend. you can test with a fused jumper wire to the power circuit of the relay socket. these two terminals will be the widest blade of the relay connector.

**gabygab** · April 10th, 2013 12:26 PM

Originally Posted by jick.cejoco

ang gulo ng post.
there are two fans for corolla, one is radiator fan and the other is a condenser fan.
when the engine coolant is still cold and the aircon is on, both radiator fan and condenser fan runs at half speed
when the coolant is around 90 degrees celsius and the a/c is off, the radiator fan runs at full speed and the condenser fan stays off
when the coolant is hot and the airconditioner is on, both radiator and condenser fan run at full speed.
with your description, check the condenser fan relay, it is marked CDS on the relay box legend. you can test with a fused jumper wire to the power circuit of the relay socket. these two terminals will be the widest blade of the relay connector.

Sorry sa magulong post sir, pls allow me to clarify.

Situation1:
Radiator no cap (removed due to pinhole leak below filler neck)
Engine operating at temp. between 80-90 deg Celcius (engine running for almost 30 mins),

1. Aircon ON, a. radiator fan cycles normally. (ON * around 80 OFF at slightly below 90. b. condenser fan cycle ON and OFF (approximately 30 sec ON, 10 sec OFF) assumption is gauge slightly not calibrated AFAIK Corolla thermoswitch range is 83 to 93 deg C

2. Aircon OFF, no condenser fan operation, no radiator fan operation up to 90 deg C (water almost boiling out of the radiator).

Question:
Is it normal? connected ba ang operation ng radiator fan sa condenser fan?

Situation2:

Aircon ON, condenser fan no operation,
Binunot ko condenser fan sa female plug
Test pin (2 pin with VOM) 12-13 V
Connected fan directly to battery, fan rotates,
Reattached fan connector to terminal after testing, fan rotates.

Turned OFF Aircon and Engine
Restarted engine and turned ON aircon
Again condenser fan do not rotate.
rotated condenser fan using VOM leads, fan rotates

Question:
Is the condenser fan defective or other electrical component?

**jick.cejoco** · April 10th, 2013 02:33 PM

Originally Posted by gabygab

Sorry sa magulong post sir, pls allow me to clarify.

Situation1:
Radiator no cap (removed due to pinhole leak below filler neck)
Engine operating at temp. between 80-90 deg Celcius (engine running for almost 30 mins),

1. Aircon ON, a. radiator fan cycles normally. (ON * around 80 OFF at slightly below 90. b. condenser fan cycle ON and OFF (approximately 30 sec ON, 10 sec OFF) assumption is gauge slightly not calibrated AFAIK Corolla thermoswitch range is 83 to 93 deg C

2. Aircon OFF, no condenser fan operation, no radiator fan operation up to 90 deg C (water almost boiling out of the radiator).

Question:
Is it normal? connected ba ang operation ng radiator fan sa condenser fan?

Situation2:

Aircon ON, condenser fan no operation,
Binunot ko condenser fan sa female plug
Test pin (2 pin with VOM) 12-13 V
Connected fan directly to battery, fan rotates,
Reattached fan connector to terminal after testing, fan rotates.

Turned OFF Aircon and Engine
Restarted engine and turned ON aircon
Again condenser fan do not rotate.
rotated condenser fan using VOM leads, fan rotates

Question:
Is the condenser fan defective or other electrical component?

this is not normal. if you have a pinhole in the cooling system plumbing, have it repaired or replace leaking component. if the system does not hold pressure, the coolant boils over. what prevents boiling over at that temperature (above 212 degrees fahrenheit of water) is the pressure in the system. for each psi of pressure increase above atmospheric pressure, there is an equivalent of around 3 degrees fahrenheit of temperature above the 212 degrees. for example: the toyota cooling system is rated at 0.9 kg/sq.cm. (around 13 psi), theoretically, the boiling point will be around 212+(13x3).
now, as far as your fan operation, your system might be using the typical toyota 3e fan system. check your fan thermoswitch first

**gabygab** · April 10th, 2013 05:19 PM

Thank you sir.

actually i'm going to replace my radiator as it has a plastic top and according to some threads here it is not repairable,
i just cannot decide what way to take, new replacement, surplus, replaced top and overhauled or "evercool" since many argue against and for about these choices.
anyways OT so back to the original topic.

Where can i get a copy of this fan system you are referring?
And by the way newly replaced na rin thermoswitch ko replacement nga lang (circuit)

**jick.cejoco** · April 11th, 2013 04:12 PM

Originally Posted by gabygab

Thank you sir.

actually i'm going to replace my radiator as it has a plastic top and according to some threads here it is not repairable,
i just cannot decide what way to take, new replacement, surplus, replaced top and overhauled or "evercool" since many argue against and for about these choices.
anyways OT so back to the original topic.

Where can i get a copy of this fan system you are referring?
And by the way newly replaced na rin thermoswitch ko replacement nga lang (circuit)

try this

**gabygab** · April 11th, 2013 04:50 PM

Originally Posted by jick.cejoco

try this

Thanks so much sir!

**gabygab** · April 15th, 2013 11:19 AM

Situation1:
Radiator no cap (removed due to pinhole leak below filler neck)
Engine operating at temp. between 80-90 deg Celcius (engine running for almost 30 mins),

1. Aircon ON, a. radiator fan cycles normally. (ON * around 80 OFF at slightly below 90. b. condenser fan cycle ON and OFF (approximately 30 sec ON, 10 sec OFF) assumption is gauge slightly not calibrated AFAIK Corolla thermoswitch range is 83 to 93 deg C

2. Aircon OFF, no condenser fan operation, no radiator fan operation up to 90 deg C (water almost boiling out of the radiator).

Question:
Is it normal? connected ba ang operation ng radiator fan sa condenser fan?

Situation2:

Aircon ON, condenser fan no operation,
Binunot ko condenser fan sa female plug
Test pin (2 pin with VOM) 12-13 V
Connected fan directly to battery, fan rotates,
Reattached fan connector to terminal after testing, fan rotates.

Turned OFF Aircon and Engine
Restarted engine and turned ON aircon
Again condenser fan do not rotate.
rotated condenser fan using VOM leads, fan rotates

Question:
Is the condenser fan defective or other electrical component?[/QUOTE]

Good Day ulit mga sir. I think problem solved...

What i have done:

Replaced the condenser fan motor (used surplus unit)
Put back the radiator cap.
Checked operation of thermoswitch (old original) Using VOM and infrared thermometer.
- Normally closed
- Open between 90-95 (Test 1 _ 90 deg celcius, test 2_ 93 deg celcius, test 3_ 95 deg celcius)
- Closed again between 80 to 85 deg C
Observe operation with the following result.

When aircon is "OFF" = Radiator fan rotates at around 95 deg C full speed
When aircon is "ON" = Condenser fan turns ON and OFF * medium speed, radiator fan turns ON and OFF *medium speed. (from 80 to slightly above 90 deg C). At above 90 deg C condenser fan and radiator cycles ON and OFF at high speed.

Next step. radiator repair/replacement.

Thanks for all the suggestion and for sir jick.cejoco's diagram.