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HELP! 03 GT Radiator fans not actualizing

 
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  #11 (permalink)  
Old 30 Sep 2017, 12:59 am
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Default Re: HELP! 03 GT Radiator fans not actualizing

Quote:
Originally Posted by ptcruisersteve View Post
The 2003 Pt Cruiser GT does not have radiator fan relays. The radiator fan is a variable speed fan only for 2003 Pt Cruiser GT.
What he said^^ it's controlled by the PCM, hence why that was the next thing I replaced
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  #12 (permalink)  
Old 30 Sep 2017, 01:02 am
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Default Re: HELP! 03 GT Radiator fans not actualizing

Quote:
Originally Posted by ptcruisersteve View Post
Some members have fixed this issue with replacing the engine coolant sensor.

Turbo Radiator Fan

The radiator cooling fan is a variable speed electric motor driven fan. The radiator fan assembly includes an electric motor, fan blade, and a support shroud that is attached to the radiator. The radiator fan is serviced as an assembly (fan motor/fan/shroud).

The variable speed radiator fan is controlled by the Powertrain Control Module (PCM) by way of a Pulse Width Modulated (PWM) signal. The duty cycle ranges from 30% for low speed operation then ramps-up to 100% for high-speed operation. This fan control system provides infinitely variable fan speeds, allowing for improved fan noise, A/C performance, better engine cooling, and additional vehicle power.

To control radiator fan operation, the PCM looks at inputs from:

Engine coolant temperature
A/C pressure transducer
Ambient temperature
Vehicle speed
Transmission oil temperature (automatic transmission only)

From the 2003 shop manual for the 2.4 liter Turbo:
Harness connector viewed from open end with the locating-locking tab at the top.
Top right is pin #1
Top left is pin #2
Bottom right is pin #3
Bottom left is pin #4
#1- black 10 gauge wire- ground
#2- violet/red 10 gauge wire- battery positive (fusible link)
#3- dark green/orange 16 gauge wire- auto-shutdown relay output
#4- dark blue/dark green 20 gauge wire- radiator fan motor control (part of PCM)

I would suggest checking the engine temperature sensor if the radiator fan is not getting any signal from the PCM on #4. Other members have had the engine temperature sensor fail causing the radiator fan not to work properly.
I did read about the coolant sensor but figured it would grow a could for a bad coolant temp sensor like my srt4 did. I'll replace it tomorrow and see what happens; I'm sure it's never been replaced on this vehicle.

Thank you for all that great info^^ now I have some basis for what to look for and test!
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  #13 (permalink)  
Old 30 Sep 2017, 02:01 am
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Default Re: HELP! 03 GT Radiator fans not actualizing

Quote:
Originally Posted by 05_ACR_SRT4 View Post
I did read about the coolant sensor but figured it would grow a could for a bad coolant temp sensor like my srt4 did. I'll replace it tomorrow and see what happens; I'm sure it's never been replaced on this vehicle.

Thank you for all that great info^^ now I have some basis for what to look for and test!
Sometimes when someone repairs a vehicle they probe the wiring enough where the wiring goes bad. You might want to check the wiring going to the PCM to see if it has been damaged before replacing the coolant temp sensor.
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Last edited by ptcruisersteve; 30 Sep 2017 at 02:21 am.
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  #14 (permalink)  
Old 30 Sep 2017, 02:07 pm
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Default Re: HELP! 03 GT Radiator fans not actualizing

"The PCM contains a voltage converter that changes battery voltage to a regulated 5 volts direct current to power the camshaft position sensor, crankshaft position sensor, manifold absolute pressure sensor, throttle position sensor, A/C pressure switch, A/C pressure transducer, and vehicle speed sensor"

"OPERATION - 5 VOLT SUPPLY - PCM OUTPUT
The PCM supplies 5 volts to the following sensors: A/C pressure transducer, Ambient Temperature sensor, Battery temperature, Camshaft Position Sensor (NGC), Crankshaft Position Sensor (NGC), Electronic Throttle Control (1.6L), Engine coolant temperature sensor, Inlet Air Temperature Sensor, Knock sensor, Linear EGR solenoid (if equipped), Manifold absolute pressure sensor, Oil Pressure Switch, Pedal Position Sensor (1.6L), Throttle position sensor, Vehicle Speed Sensor"

For the turbo radiator fan control, the PCM is reading 5-volt reference system signals from Engine coolant temperature sensor, A/C pressure transducer, Ambient temperature, Vehicle speed sensor, Transmission oil temperature (automatic transmission
only)

"The PCM uses these inputs to determine when the fan should operate and at what speed."

1. Pin #2 vt/rd 10 gauge - battery power There is a fusible link in this circuit near the battery. Suggest checking the fusible link.

2. Test for voltage at pin numbers 2 & 3 at the radiator connector.
2a. Pin #2 should have constant 12 volt battery power.
2b. When the ignition is on, pin #3 should have 12 volt power through the auto-shutdown relay. If the relay is not functioning, many other systems will also be shut down.

If either pin is missing voltage, you need to work backwards along the circuit to find the fault.
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  #15 (permalink)  
Old 02 Oct 2017, 09:42 am
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Default Re: HELP! 03 GT Radiator fans not actualizing

Quote:
Originally Posted by ptcruisersteve View Post
Sometimes when someone repairs a vehicle they probe the wiring enough where the wiring goes bad. You might want to check the wiring going to the PCM to see if it has been damaged before replacing the coolant temp sensor.
Exactly what happened to my 03GT. Dealer fixed the fan, 3-4 years later out of warranty we had the same/similar problem and took it to a local guy. He was about to do the fan when he realized noticed the untaped hole in the harness.
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  #16 (permalink)  
Old 31 Oct 2017, 11:06 am
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Default Re: HELP! 03 GT Radiator fans not actualizing

Quote:
Originally Posted by 05_ACR_SRT4 View Post
I'm a new member here but long time lurker.
I have seen the many threads about the 03 GT fan issues. My radiator fan does not turn on regardless of the A/C being on or not, I purchased a new aftermarket fan, it did not fix the problem.
I replaced the ECU(mileage and VIN flashed into it) still the fan does not turn on, any suggestions?

Also i did look at the grounds that i could see in the engine bay and they all seemed solid, ASD relay swapped with horn relay and ASD fuse checked but still no go. Does anyone know of all the grounds to look for? if so can you pin point them please? i'm not too familiar with the pt gt platform, only familiar with srt4.

thanks a million
You want to get rid of the old non working unit?
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