Do Cooling Fans turn on when driving on Highwys?

1419 Views 3 Replies 3 Participants Last post by gdanaher, Aug 26, 2010

qprint2

Discussion Starter · Aug 25, 2010

Just curious if the radiator fans come on when driving over 80km/hr.
2004 Camry V6

I have one radiator fan located on passenger side not turning on when sitting in traffic. I disconnected 2 wires leading to lower side of radiator temperature switch. Put an ohmmeter to them and it read open, even when the car was hot. I read somewhere that the ohmmeter should read some value depending on the temperature of the coolant. If i short the 2 wires, the cooling fan turns on. Ive put a manual switch to turn the fan on or off when i wanted, until i get this problem solved. Does highway driving turn on the fan normally ?

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njerald

· #2 · Aug 26, 2010

qprint2 said:
Just curious if the radiator fans come on when driving over 80km/hr.
2004 Camry V6

I have one radiator fan located on passenger side not turning on when sitting in traffic. I disconnected 2 wires leading to lower side of radiator temperature switch. Put an ohmmeter to them and it read open, even when the car was hot. I read somewhere that the ohmmeter should read some value depending on the temperature of the coolant. If i short the 2 wires, the cooling fan turns on. Ive put a manual switch to turn the fan on or off when i wanted, until i get this problem solved. Does highway driving turn on the fan normally ?

They turn on based on coolant temp. at no speed or any speed.

Ambient temp., engine load, A/C operation and cooling system condition are variables that determine coolant temp/fan operation.

GEN6 testing:

ON-VEHICLE INSPECTION
1. INSPECT COOLING FAN SYSTEM

(a) Put the vehicle in the following conditions:
(1) The ignition switch is off.
(2) The coolant temperature is less than 95

°C (203°F).
(3) The battery voltage is between 9 and 14 V.
(4) The A/C switch is OFF.
(b) Connect the 400 A probe of the ammeter to terminals M+ (M) and M+ (S) of the cooling fan motor.
(c) Turn the ignition switch on (IG) and wait for approximately 10 seconds. Check that the fan stops.
(d) Start the engine. Check that the fan stops with the engine idling.
HINT:
• Make sure that the radiator engine coolant temperature is less than 95°C (203°F).
• Turn the A/C switch OFF.
(e) Check that the fan operates when the A/C switch is turned ON (MAX COOL and the magnet clutch is operating).

Standard current : Without trailer hitch
Standard current : With trailer hitch

HINT:
The coolant temperature is less than 95

°C (203°F).
(f) Check that the fan operates when the engine
coolant temperature sensor connector is
disconnected.

Standard current : Without trailer hitch
Standard current : With trailer hitch
Item Specified Condition
Cooling fan motor 2 to 8 A
Cooling fan motor No. 2 2 to 8 A
Item Specified Condition
Cooling fan motor 2 to 11 A
Cooling fan motor No. 2 2 to 11 A
Item Specified Condition
Cooling fan motor 2 to 11 A
Cooling fan motor No. 2 2 to 11 A
Item Specified Condition
Cooling fan motor 2 to 15 A
Cooling fan motor No. 2 2 to 15 A

g) After the engine is warmed up, check that the fan operates as shown in the illustration on the left.
HINT:
• The coolant temperature at which the fan starts operating is approximately 95

°C (203°F).

Check your GEN5 Service Manual..........

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qprint2

Discussion Starter · #3 · Aug 26, 2010

my car is a Gen 5. Would the procedures be the same for this ?

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gdanaher

· #4 · Aug 26, 2010

Yes, this is standard stuff across the industry. Essentially the same procedure would work on a Ford or Chevy. The sensor is going to be open at low temps and at some point it will get hot and close. When closed, the circuit is completed and the fan comes on.

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