2000 Caravan-Engine cooling fans not running, replaced temperature sensor and fan relay, still not working-HELP

How long does it run? some cars will run the fan for a few minutes to ensure that too much heat does not build up under the hood. Wait for 5 minutes and see if it is still running when the engine is off. If it is you may have a bad temperature sensor. Does the engine temperature gauge work properly?

That would depend upon where you placed the voltage on the relay. And even then not necessarily so. The only thing you verified with the test was that the fan itself is okay. The cooling fan relay is powered from the ECM (computer). The ECM will power the cooling fan whenever one of two conditions exists:

1. Engine temperature exceeds about 210 degrees F. his temp is determined by the coolant temperature sensor.
2. The A/C is turned on. The fans must run at all times when A/C is on.

So, with the engine running, turn on the A/C. If the cooling fan activates, then you know the ECM, relay, and fan is OK. If the fan then doesn't activate when the engine temp gets high, it is the coolant temperature sensor that is the culprit.

If the fan doesn't run when you turn on the A/C, then, since you know the fan works, try the relay next, because other than wiring, the only other item that could be wrong is the ECM (and you don't want to go there!)

There is no relay on the cooling fan circuit.
If the cooling fan is not operating, check fuse #105 (20 AMP), in the underhood junction box, right front of engine compartment.
If fuse is good then test to make sure fan is getting power.
If no power then could be bad cylinder head temperature sensor, hydraulic fan solenoid, a/c cycle switch or the PCM.
If it has power but doesn't come on then fan motor is bad.

It can be issue with faulty motor or its faulty fan control relay.
Bother are to be inspected.Test volt at fan relay and fan motor.-------------
For more help,i suggest you to go through the troubleshooting links mentioned below:-----Click the link below:------

How to replace Cooling Fan on Acura Car models?

http://repairhelpcenter.blogspot.com/2011/11/how-to-replace-cooling-fan-on-acura-car.html
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OBD Code P1490 low speed fan relay ckt open-short
http://schematicsdiagram.blogspot.com/2012/11/obd-code-p1490-low-speed-fan-relay-ckt.html
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Engine cooling components working?

http://repairhelpcenter.blogspot.com/2011/11/engine-cooling-components-working.html

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How does Vehicles Engine cooling system works?

http://repairhelpcenter.blogspot.com/2011/11/how-does-vehicles-engine-cooling-system.html

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Hyundai Sonata cooling fan not working

http://schematicsdiagram.blogspot.in/2012/02/hyundai-sonata-cooling-fan-not-working.html

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Fuel pump relay and cooling fan relay troubleshooting on 1997 ford thunderbird?

http://repairhelpcenter.blogspot.com/2011/10/fuel-pump-relay-and-cooling-fan-relay.html
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Fan belt routing diagram for 2004 Volkswagen Jetta?

http://carbeltrouting.blogspot.com/2011/12/fan-belt-routing-diagram-for-2004.html
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Timing belt, drive belt, serpentine belt, accessory belt, fan belt, engine belt routing diagrams for all types of car models?

http://carbeltrouting.blogspot.in/2012/02/timing-beltdrive-beltserpentine.html
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A/C, heater, defroster fan, not working?

http://technoanswers.blogspot.in/2012/02/ac-heater-defroster-fan-not-working.html
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Blower fan not running on Isuzu trooper?

http://technoanswers.blogspot.in/2012/02/blower-fan-not-running-on-isuzu-trooper.html
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How to replace blower motor fan assembly on 2000 GMC Yukon?

http://repairhelpcenter.blogspot.com/2012/01/how-to-replace-blower-motor-fan.html
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Heater AC or defroster fan not working on KIA?

http://technoanswers.blogspot.in/2012/02/heater-ac-or-defroster-fan-not-working.html
------------These will help.Thanks.

COOLING FANS NOT RUNNING

It is normal for the A/C air to warm up a little when stopped. Less airflow thru the condensor. It is normal for the engine temperature gage to rise up to about the 80% mark on its scale before the cooling fan kicks on. The gage will also show about the same reading on the first start of the day, until the thermostat opens.

If the fan(s) are not working properly the A/C air and engine temperature will rise. If you have a belt driven clutch fan, the clutch may be worn out. All cooling fans kinda sound like miniature jet engines when its hot out, more so when the A/C is on. Replacing the clutch is all you can do for a belt driven fan. Electric fans are more complicated....
Check all main power electrical connections first.... Electric Fan(s) not working, Checking the fan(s), relay, fuse and engine temperature sensor's.
Verify that the fans work by unplugging them and run jumper wires to the fan(s) from the battery. If they run, your problem lies elsewhere. If either does not run, it's the motor.
Next thing to check is for power at the fan connectors. You have to be cautious doing this because the engine needs to be running and warm if not almost hot, and the A/C also needs to be on. (Both must be on and running for the duration of this checklist.) The A/C fan is on the passenger side and should come on almost the instant the A/C is turned on. It is also the secondary engine cooling fan and should cycle on and off in relation to engine temperature. Use a test light to probe the two wires on each fan. If you find power the fan motor(s) is/are probably bad. If there is no power to fans, roll up your sleeves!

The temperature switch is usually located above the oil filter. If the dash gage is working, its probably OK. Next is the Fan Control Temperature Sensor, located IN or CLOSE to the thermostat housing. You will find out if it is working later is this checklist. I just wanted you to know where it is. Next is the relays and fuse's. Usually located in the engine compartment on the passenger side power distribution box. You will need to remove anything over the cover to open it. If the fuses are OK, tap on the relays or pull them out and push back in. If the fans are still not running, pull a relay and probe the socket terminals for power. Two or three of the terminals should have power, usually criss-cross from each other. Two are hot battery power, and the third is the "signal" voltage which triggers the relay to send 12V battery power to the fan. This signal voltage comes from the sensor at the thermostat. If only two terminal's have power, then I would replace the thermostat sensor if not both sensors.

Hope this is clear as mud! and helps! Please let me know what you find.

COOLING FANS NOT RUNNING

It is normal for the A/C air to warm up a little when stopped. Less airflow thru the condensor. It is normal for the engine temperature gage to rise up to about the 80% mark on its scale before the cooling fan kicks on. The gage will also show about the same reading on the first start of the day, until the thermostat opens.

If the fan(s) are not working properly the A/C air and engine temperature will rise. If you have a belt driven clutch fan, the clutch may be worn out. All cooling fans kinda sound like miniature jet engines when its hot out, more so when the A/C is on. Replacing the clutch is all you can do for a belt driven fan. Electric fans are more complicated....
Check all main power electrical connections first.... Electric Fan(s) not working, Checking the fan(s), relay, fuse and engine temperature sensor's.
Verify that the fans work by unplugging them and run jumper wires to the fan(s) from the battery. If they run, your problem lies elsewhere. If either does not run, it's the motor.
Next thing to check is for power at the fan connectors. You have to be cautious doing this because the engine needs to be running and warm if not almost hot, and the A/C also needs to be on. (Both must be on and running for the duration of this checklist.) The A/C fan is on the passenger side and should come on almost the instant the A/C is turned on. It is also the secondary engine cooling fan and should cycle on and off in relation to engine temperature. Use a test light to probe the two wires on each fan. If you find power the fan motor(s) is/are probably bad. If there is no power to fans, roll up your sleeves!

The temperature switch is usually located above the oil filter. If the dash gage is working, its probably OK. Next is the Fan Control Temperature Sensor, located IN or CLOSE to the thermostat housing. You will find out if it is working later is this checklist. I just wanted you to know where it is. Next is the relays and fuse's. Usually located in the engine compartment on the passenger side power distribution box. You will need to remove anything over the cover to open it. If the fuses are OK, tap on the relays or pull them out and push back in. If the fans are still not running, pull a relay and probe the socket terminals for power. Two or three of the terminals should have power, usually criss-cross from each other. Two are hot battery power, and the third is the "signal" voltage which triggers the relay to send 12V battery power to the fan. This signal voltage comes from the sensor at the thermostat. If only two terminal's have power, then I would replace the thermostat sensor if not both sensors.

Hope this is clear as mud! and helps! Please let me know what you find.

There isn't an actual separate sensor for the cooling fans, instead the Engine Coolant Temperature [ECT] sensor sends a constant signal to the engine computer telling it the current coolant temp and the computer then decides when to close a relay which sends power to the cooling fan[s]. The cooling fans won't be on, even if the engine is running, unless either the a/c system is on and working or the coolant temperature reaches about 218 - 220 degrees at which point the cooling fans will be turned on and run until the coolant reaches a temperature of about 210 degrees and then it will turn off. If the a/c is on then the cooling fan[s] will be turned on and stay running to remove the heat from the a/c condensor all the while the a/c is left on. The fan[s] rarely come on at highway speeds because once the vehicle is over about 35 mph there is enough air being forced through the radiator to keep everything cool. If the fan won't work at all I usually check for a blown 30 amp fuse in the underhood fuse junction box or you could have a fan motor that has simply failed. Hope this helps a bit and good luck!

check for battery power at pin 4 of rad fan relay connector..ground at pin 1..jump pins 3 and 4..fans should work..if not,check harness about 3-4 inches away from relay connector..have seen these corrode..if fans work,the engine controller may not be grounding relay..any codes in engine controller?engine light on?

Replace the cooling fan sensor.

Fifteen minutes! you have bigger problems than only the fans the fans are controlled by a thermo switch that is heated by the coolant, If you have no coolant the sensor cannot activate But fifteen minutes seems like you may have a headgasket problem and steam cannot heat the coolant sensor.OperationNotesThe electric cooling fan operates when the engine cooling temperature exceeds a certain value. The cooling fan on this engine is controlled by the Powertrain Control Module (PCM) . The PCM turns the cooling fan ON by grounding the coil of the cooling fan relays when certain conditions are met. When the A/C is requested, the cooling fan will also be turned ON.

Power for the cooling fan motors are supplied through Maxifuses(R). The cooling fan relays are energized when current flows from the fuses in the Underhood Accessory Wiring Junction Block, and through the relay coils to ground through the PCM. The Coolant Fan 1 Relay Control Circuit is grounded for low speed fans operation. During low speed fans operation, both fans run at a slow speed. The Coolant Fan 1 Relay Control Circuit is grounded for high speed operation. During high speed fans operation, both fans run at high speed.

IMPORTANT: When certain Diagnostic Trouble Codes (DTCs) are present, the PCM may command the cooling fans to run all the time. Perform the A Powertrain On Board Diagnostic (OBD) System Check prior to diagnosing the engine cooling fans.

For more information regarding the Charging System, refer to Charging System Description , and Charging System Circuit Description in Starting and Charging.

If a problem that involves the low speed cooling fan relay control circuit exists, DTC P0480 Cooling Fan Relay 1 Control Circuit should set. If the problem affects the high speed cooling fan relay control circuit, DTC P0481 Cooling Fan Relay 2 Control Circuit should set. A problem with the ECT sensor should set DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage, DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage, DTC P1114 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage, DTC P1115 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage. Any of these DTCs will affect cooling fan operation and should be diagnosed before using the Electric Cooling Fan Diagnosis.

For more information regarding the Cooling System refer to Engine Cooling Fan Description - Electric, and Cooling System Description in Cooling System.


Here is the electrical schematic and how it all is suppose to work,
If you need any further help please contact me Thank you,Randy If you find this information helpful please give me a good rating

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