Some times cooling fan will not start and the car got hot , i tested the fan and it is working ok from external supply, also i changed its relay, but i changed the sensor 10 times !! , when i change a sensor it works good for few days only then i have to change it again, please help >

Both radiator cooling fans are running all the time ? Key off ? The cooling fan opperation
HOW they work
Cooling Fan Control
The engine cooling fan system consists of 2 cooling fans and 3 relays. The relays are powered by the battery positive voltage circuit and controlled by a switched ground from the powertrain control module (PCM).
During low speed operation, the PCM supplies the ground path for the low speed cooling fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan low relay coil, closes the relay contacts, and supplies battery positive voltage from the COOL FAN LO fuse through the cooling fan motor supply voltage circuit to the cooling fan. During high speed operation the PCM supplies the ground path for the cooling fan low relay through the low speed cooling fan relay control circuit. After a 3-second delay, the PCM supplies a ground path for the cooling fan high relay and the s/p cooling fan relay through the high speed fan relay control circuit.
The PCM commands the fan on under the following conditions:
• Engine coolant temperature exceeds approximately 98°C (208°F) Low Fan Speed
• Engine coolant temperature exceeds approximately 102°C (216°F) High Fan Speed
• A/C refrigerant pressure exceeds 361 kPa (52 psi) Low Fan Speed
• A/C refrigerant pressure exceeds 2100 kPa (300 psi) High Fan Speed
• When the engine coolant temperature exceeds 112°C (234°F) at key off, the fan high speed will run for up to 300 seconds. If within that time frame 102°C (216°F) is reached then fan speed will change from high to low speed. If within that time frame 99°C (210°F) is reached then fan speed will change from low to off.
The PCM commands the fan off under the following conditions:
• A/C is requested and engine speed exceeds 6,240 RPM
• Engine coolant temperature exceeds approximately 99°C (210°F) turns the cooling fans from low to off.

sounds like one of the relays are stuck closed .

Cooling Fan Always On
Step
Action
Yes
No
Schematic Reference: Engine Cooling Schematics , HVAC Schematics in HVAC Systems - Manual
Connector End View Reference: Cooling System Connector End Views
DEFINITION: One or both engine cooling fan motors run continuously in high or low speed.
1
Did you perform the Diagnostic System Check - Vehicle?
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With a scan tool, command the Fans Low Speed ON and OFF.
Are one or both cooling fans ON?
Go to Step 3
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3
Are both cooling fans running continuously?
Go to Step 4
Go to Step 6
4
Are both cooling fans running continuously in high speed?
Go to Step 5
Go to Step 7
5
Test the low reference circuit of the A/C refrigerant pressure sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 18
Go to Step 14
6
Important: The S/P relay is located under the front bumper on the drivers side of the vehicle.
Remove the cool fan S/P relay.
Did the right cooling fan turn OFF?
Go to Step 10
Go to Step 8
7
Remove the cool fan LOW relay.
Did the cooling fans turn OFF?

get a multi- meter so you can test the fan and coolant sensor

Take it to a qualified repair shop that has diagnostic information (shop manual ) An has a professional scan tool . Changed what sensor ? Coolant temp ? You don't guess an just replace parts . Doing a full vehicle scan ,checking for DTC'S in all the modules on the vehicle.

ENGINE HOT A/C OFF
Refer to Cooling System Description and Operation
Do the radiator cooling fans work ?
The engine cooling fan system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a Series/Parallel configuration that allows the engine control module (ECM) to operate both fans together at low or high speeds. The cooling fans receive positive voltage from the cooling fan relays which receive battery positive voltage from the underhood fuse block.
During low speed operation, the ECM supplies the ground path for the low speed fan relay, which is Fan 1 Relay, through the low speed cooling fan relay control circuit. This energizes the low speed fan relay coil, closes the relay contacts, and supplies battery positive voltage from the Fan 1 Fuse through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the Series/Parallel relay, which is Fan 2 Relay, and the right cooling fan. The result is a series circuit with both fans running at low speed.
During high speed operation, the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. The ECM grounds the high speed fan relay, which is Fan 3 Relay and the Series/Parallel relay through the high speed cooling fan relay control circuit. This energizes the Series/Parallel relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the high speed fan relay coil is energized, the relay contacts close to provide battery positive voltage from the Fan 2 Fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.
When the requests for fan activation is withdrawn, the fan may not turn OFF until the ignition switch is moved to the OFF position or the vehicle speed exceeds approximately 10 mph. This is to prevent a fan from cycling ON and OFF excessively at idle

DTC P1258: Engine Coolant Overtemperature - Protection Mode Active

The relay maybe fine but the PCM - engine computer that controls the relay to turn on the fan may not be . Rather then guessing an changing the coolant temp. sensor have it checked for DTC'S - diagnostic trouble code's . 10 to 1 if the sensor was bad the check engine light would be on , indicating a code was stored.

Cooling Fan Control
The engine cooling fan system consists of 1 cooling fan and 1 relay. The relay is powered by the battery positive voltage circuit and controlled by a switched ground from the powertrain control module (PCM).
During operation, the PCM supplies the ground path for the cooling fan relay through the cooling fan relay control circuit. This energizes the cooling fan relay coil, closes the relay contacts, and supplies battery positive voltage from the cooling fan fuse through the cooling fan motor supply voltage circuit to the cooling fan. The cooling fan motor is grounded through its own ground circuit.
The PCM commands the fan ON under the following conditions:
• Engine coolant temperature exceeds approximately 106°C (223°F).
• A/C refrigerant pressure exceeds 1310 kPa (190 psi).
• A/C is requested and vehicle speed is below 100 km/h (62 mph) with A/C pressure above 1413 kPa (205 psi).
• Vehicle speed is less than 8 km/h (5 mph) for more than 750 seconds. The fan will turn OFF when vehicle speed is greater than 8 km/h (5 mph) for more than 20 seconds.

Hooking up a scan tool that can view sensor data would be the best an easiest way to diagnose . Some scan tools have bi-directional controls , which means you could turn on the fan with scan tool ,too see if computer has control . Guessing doesn't fix cars most of the time , testing does .

op
why not post symptoms first and not a barrage of parts.
must we decode that to a symptom,. kinda hard right.

I will not guess. what is wrong, nor what is not working on your car. now what fans you are talking about, up to 4 fans on cars.

cab blower fan (wild guess blower is ok) and so is HVAC, ?
radiator fans
Condenser fan.

my wild guess to , engine over heats?????????
if yes, the scan it first. no not last FIRST.
it dont work like you think its not a 1988 Samurai.
sorry,
on modern cars, they got smarter, the engine goes
gee the PCM knows water temp why have a fan temp regulator.
hark , now it dont. (saves cash on useless parts)
but has a relay , (well until you have my car and the relay is now 100% electronic, called a huge transistor)
we've used this tech in industry for years, but car makers just learning how still.
i digress. but evolution and history helps diagnosis.
what is there?

Ill look for you, ive posted this 100s of times
the book is 4 bucks to see online. the real deal
lets look now.
XL-7 (the dash matters big time)
answering for , overheats engine, and fans on RAD dead.
(some are staged, PCM brains... now. and also chain ops based on if A/C is on or not) facts.
first I see 2 fans... ok.
the next page shows nice block diagram of the fan system
yup, NOT Simple.

ill post those words for you.
"The engine cooling fan system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the engine control module (ECM) to operate both fans together at low or high speeds. The cooling fans receive positive voltage from the cooling fan relays which receive battery positive voltage from the underhood fuse block.
During low speed operation, the ECM supplies the ground path for the low speed cooling fan relay which is fan 1 relay through the low speed cooling fan relay control circuit. This energizes the low speed fan relay coil, closes the relay contacts, and supplies battery positive voltage from the fan 1 fuse through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the series/parallel relay which is fan 2 relay, and the right cooling fan. The result is a series circuit with both fans running at low speed.
During high speed operation the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. The ECM grounds the high speed fan relay, which is fan 3 relay, and the series/parallel relay, which is fan 2 relay through the high speed cooling fan relay control circuit. This energizes the series/parallel relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the high speed fan relay coil is energized closing the relay contacts and provides battery positive voltage from the fan 2 fuse 1 on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.
When the request for fan activation is withdrawn, the fan may not turn OFF until the ignition switch is moved to the OFF position or the vehicle speed exceeds approximately 16 km/h (10 mph). This is to prevent a fan from cycling ON and OFF excessively at idle.
end quote.

i bet you didnt scan it , like 99.9 % of all posters here dont.
DTC Descriptors
DTC P0480: Cooling Fan Relay 1 Control Circuit
DTC P0481: Cooling Fan Relay 2 Control Circuit
DTC P0691: Cooling Fan Relay 1 Control Circuit Low Voltage
DTC P0692: Cooling Fan Relay 1 Control Circuit High Voltage
DTC P0693: Cooling Fan Relay 2 Control Circuit Low Voltage
DTC P0694: Cooling Fan Relay 2 Control Circuit High Voltage
Diagnostic Fault Information

is the ECT showing overheat, yes no?
if yes, it must operate a fan or 2.
the book even covers all tests for fans dead, in a large truth table.
both the FSM and alldata.com have that, its no secret ,its published in 4 major places.

lets back up
if the engine coolant is low (no that side tank the engine and rad)
the ECT will lie. if that happens the fans may not come one
that is because the ECT is useless measuring air, for water.
that water must touch ECT for ECT to work.
this is FIRST
then scan the ECT does it show overheating, IT must if it IS overheating. fix that next if it lies to you,(IR gun in hand)

The system has staged fans.
i cant find the trip points in my crappyy online pages.
but is like 225f then 250f trips. is my guess...
about. if the engine over heats, check fuses first then scan it.
it will simply tell you why its bad.
eg, fan1 output dead.
or if you hot wire a fan and its dead, then it is.
(only on cars with non modulated fans,,hot wire them,else not.)

now the link to the 4 buck real book.
the non dash XL7 (my guess) you this pick yourself... cant see car.
https://suzukipitstopplus.com/Products/10182-2007-xl7-service-manual.aspx

this is how it really works
the ECU has software that decide trip points for fans.
hard coded, this is. based on how hot it is and if A/C is on not.
its way smarter than 1988 and better.
the DTC errors can see an open line, shorted to ground or stuck 12v.(runs all time error)
(tells you relay is good or not)

no scanner no joy , sorry, tis a fact.....

Are you talking about the radiator fan? How hot does the engine get in degrees F? Some makes and models, the radiator fan won't turn on till about 220 degrees F. Check for applicable trouble codes, see if any code that refers to the radiator fan circuit or coolant temp sensor? Some of the national brand auto stores will check codes for free.

Of course, as far as overheating in general, you have the thermostat--water pump and other possible issues. Are you losing coolant?

remove the relay and test it across the battery ,the two big connectoprs are the fan power supply and two smaller ones are the relay ,test the smaller one across the battery and see if it clicks ,if they click then test the big ones for continuety when the small ones are connected and gone click .Simple if all ok then test for power in the big connectors in the relay holder ,one of them should read a permanant 12v supply

FAN NOT WORKING

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.

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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

--------------

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

---------------

Engine cooling components working?

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

----------

How does Vehicles Engine cooling system works?

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

---------------

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

--------------

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

---------

How to replace blower motor fan assembly on 2000 GMC Yukon?

http://repairhelpcenter.blogspot.com/2012/01/how-to-replace-blower-motor-fan.html

----------

Heater AC or defroster fan not working on KIA?

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

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These will help.

Thanks.

This code pertains to the cooling fan relay. Change the relay if necessary. When the engine heats up the sensor will send the signal to the relay to start the fan. If the engine is hot & the fan has not started, change it.Good luck!

You can flip flop relays with other like relays to confirm that all relays are ok.
Too, you can bring power and ground to the fan to confirm the fan is ok.
Then next, you can check the resistance of the coolant temperature sensor and confirm it is ok ( typically resistance will be different from cool engine to hot engine )
Let me know what your tests come up with.