Question about 2002 Dodge Ram Maxi

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Cooling fan relay control ciruit

Is this normal problem

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  • Dodge Master
  • 5,568 Answers

Are you sure it isn't only a failed thermoswitch?
There isn't normally much of a circuit; the fan motor is directly or indirectly controlled by a bimetal switch that is screwed into the lower radiator tank. That switch could control a relay but it isn't common to do it that way, it would be better since that kind of switch doesn't handle fairly heavy currents as the fans need so a relay would relieve it from carrying no more than a couple hundred milliamperes at the most.  

Posted on Jan 14, 2009

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Fan is not working on 2001 Chevy Silverado 2500 truck radiator fan motor?


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 powertrain control module (PCM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood fuse block.
During low speed operation, the PCM supplies the ground path for the low speed fan 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 low fan 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 cooling fan s/p relay and the right cooling fan. The result is a series circuit with both fans running at low speed.
During high speed operation the PCM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. After a 3 second delay, the PCM supplies a ground path for the high speed fan relay and the cooling fan s/p relay through the high speed cooling fan relay control circuit. This energizes the cooling fan s/p 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 high fan fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed.
Your best bet would be to take your vehicle to a qualified repair shop !
Relay Driven Dual Cooling Fan Diagnostics

Aug 19, 2016 | 2001 Chevrolet Silverado 2500

2 Answers

Where is the fuse for motor fan in uplander 2006?


there is 2 fuses that you have to check
one will be in the big fuse assembly in the engine bay, the other probably in the fuse assembly in the cab
If they prove ok then it is possible that the coolant temperature SENSOR is faulty and needs replacing
don't confuse it with the temperature sender which operates the temp gauge.

Aug 10, 2015 | 2006 Chevrolet Uplander

1 Answer

I have an 05rendezvous,need to locate switches for cooling system,fans aren't co ming on & now I'm going to need a new radiator,cuz plastic broke.But it broke before fans gave out.Which I changed stat


The engine cooling fan system is controlled by the body control module (BCM) and the powertrain control module (PCM) or engine control module (ECM). The BCM performs the calculations as to how long, when and what speed the cooling fans should turn on. The BCM then sends a class 2 message to the PCM/ECM to engage the cooling fan relays. If there is a malfunction with the BCM, the PCM/ECM will control the engine cooling fans independently. The engine cooling system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the PCM/ECM to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood accessory wiring junction block. The ground path is provided at G100.
During low speed operation, the PCM/ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage from the cool 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 cooling 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 PCM/ECM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3 second delay, the PCM/ECM supplies a ground path for the cooling fan 3 or S/P relay and the cooling fan 2 relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 2 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the cooling fan 2 relay coil is energized closing the relay contacts and provides battery positive voltage from the cool 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 there own ground path. The result is a parallel circuit with both fans running at high speed.
The BCM and PCM/ECM command Low Speed Fans on under the following conditions:
?€¢
Engine coolant temperature exceeds approximately 106?°C (223?°F).


?€¢
A/C refrigerant pressure exceeds 1 310 kPa (190 psi).


?€¢
After the vehicle is shut off if the engine coolant temperature at key-off is greater than 140?°C (284?°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.

The BCM and PCM/ECM command High Speed Fans on under the following conditions:
?€¢
Engine coolant temperature reaches 110?°C (230?°F).


?€¢
A/C refrigerant pressure exceeds 1 655 kPa (240 psi).


?€¢
When certain DTCs set.


The three relays are located in the under hood fuse / relay box ! You need to have it checked for DTC'S -diagnostic trouble codes ! An you need a GM Tech 2 scan tool !
This diagnostic procedure supports the following DTCs:
?€¢
DTC P0480 Cooling Fan 1 Relay Control Circuit


?€¢
DTC P0481 Cooling Fan 2 and 3 or S/P Relay Control Circuit


?€¢
DTC P0691 Cooling Fan 1 Relay Control Circuit Low Voltage


?€¢
DTC P0692 Cooling Fan 1 Relay Control Circuit High Voltage


?€¢
DTC P0693 Cooling Fan 2 and 3 or S/P Relay Control Circuit Low Voltage


?€¢
DTC P0694 Cooling Fan 2 and 3 or S/P Relay Control Circuit High Voltage


  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the Fans Low Speed ON and OFF.
Do the low speed engine cooling fans turn ON and OFF with each command?
Go to Step 3
Go to Step 4

3

Important:: A 3 second delay occurs before the powertrain control module (PCM)/engine control module (ECM) changes the cooling fan speed.
With a scan tool, command the Fans High Speed ON and OFF.
Do the high speed engine cooling fans turn ON and OFF with each command?

Aug 08, 2015 | Cars & Trucks

2 Answers

Why does my fan keep running in my 2003 Volvo S 60 after the car is off?


It can be faulty fan relay.The relay is not turning the system off.Or its wire short issue.Even with ignition off ,the fan relay is getting power so its not letting the fan to turn off.Bypass the fan control relay and see if still the fan works with ignition off or not.

For more troubleshooting check the link below:------

Cooling Fan Stays ON with Ignition Off?

http://whatisbyme.blogspot.in/2012/07/cooling-fan-stays-on-with-ignition-off.html
--------------

Cooling fan relays location ?

http://technoanswers.blogspot.in/2012/02/cooling-fan-relays-location-on-1998.html
------------

DIC says "COOLING FAN FAULT"?

http://schematicsdiagram.blogspot.com/2011/12/dic-says-cooling-fan-fault.html
----------

Heater fan and headlights will not turn off with ignition off?


http://technoanswers.blogspot.com/2012/01/heater-fan-and-headlights-will-not-turn.html


-----------

Fuel pump relay and cooling fan relay troubleshooting ?

http://repairhelpcenter.blogspot.com/2011/10/fuel-pump-relay-and-cooling-fan-relay.html

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

Where Is Radiator Fan relay and Fuse Located?

http://schematicsdiagram.blogspot.com/2011/12/where-is-radiator-fan-relay-and-fuse.html

------------
These will help.
Thanks.

Nov 28, 2012 | Volvo S60 Cars & Trucks

1 Answer

The a/c fan comes on and off when the car is not running. Sounds like a relay, if so where is it located?


this relay is located at right rear of the engine compartment, this relay is for the normal speed control for the cooling fan, all other relays for ac and cooling is controled by the computers, you may have a bad high preasure switch for the ac, you said ac fan, i assume you are talking about the cooling fan for the ac at the radiator if this is correct then theres relay where i said. hope this helps.

Nov 01, 2010 | 2001 BMW 5 Series

1 Answer

Code p1652 on a 1996 pontiac grand prix does anyone know what it means the book for computer codes is incomplete


Trouble code P1652 means: Cooling Fan 2 Relay Control Circuit Malfunction

I would start by checking power supply to the cooling fans,making sure the coolant system is full,& using a scn tool to verify the proper operation of the cooling fan system.Here is some info to help you.

The Powertrain Control Module (PCM) controls the operation of the cooling fans. This is accomplished by providing a ground path for the cooling fan relay coils within the PCM. The relay contacts will close and complete the circuit between the fusible link at the battery junction block and the fan motors. Whenever there is a fan ON request both fans will be running.

Power for the fan motors is supplied through a fusible link at the battery junction block. Battery positive voltage is applied to the cooling fan relay contacts and coils. The cooling fan relays are energized when current flows through the relay coils to ground at the PCM. The cooling fan relay #1 control circuit is used for low speed cooling fan operation. The cooling fan relay #1 control circuit and the cooling fan relay #2 and #3 control circuit are both grounded for high speed fan operation. The cooling fan relay control circuits are monitored by the PCM. Before using the Electric Cooling Fans diagnostic tables be sure to perform the Powertrain On-Board Diagnostic System Check. If diagnostic trouble codes P1651 or P1652 are present, use the appropriate DTC diagnostic tables prior to performing Electric Cooling Fans diagnostics.

Important:
When certain Diagnostic Trouble Codes (DTCs) are present, the PCM may command the cooling fans to run all the time. It is important to perform the Powertrain On-Board Diagnostic System check prior to diagnosing the engine cooling fans.The PCM will complete the ground path for cooling fan relay #1 under any of the following conditions:
- When engine coolant temperature exceeds 105°C (221°F)
- When A/C is requested and ambient temperature is greater than 10°C (50°F)
- When A/C refrigerant pressure is greater than 190 psi (2 volts)

For high speed cooling fans operation, the PCM will delay control of the cooling fan #2 and #3 relays for 6 seconds. The 6 second delay ensures that the cooling fan electrical load will not exceed the capacity of the system. The PCM will complete the ground paths for cooling fan relays #1, #2, and #3 under any of the following conditions:
- When engine coolant temperature exceeds 113°C (235°F)
- When A/C refrigerant pressure is greater than 275 psi (2.9 volts)

If a problem that involves the low speed cooling fan relay control circuit (cooling fan relay #1 control) exists, DTC P1651 should set. If the problem affects the high speed cooling fan relay control circuit (cooling fan relay #2 and #3 control), DTC P1652 should set. A problem with the ECT sensor should set DTC P0117, P0118, P1114, or P1115. Any of these DTCs will affect cooling fan operation and should be diagnosed before using the Electric Cooling Fan Diagnosis table. The Electric Cooling Fan Diagnosis table should be used to diagnose the PCM controlled cooling fans only if no DTC is set.
Hope this help to solve your poblem (remember rated and comment this help).

Mar 21, 2010 | 1996 Pontiac Grand Prix

1 Answer

Cooling fans do not run normally or in AC mode on 2003 VW GTI VR6


Check cooling fans not faulty - run freely.
Check the operation of the cooling fan control relay.
Replace relay, and observe if this fixes the problem.

Jul 17, 2009 | 2003 Volkswagen GTI

1 Answer

I'm trying to find out how many cooling fan relays are in a 1999 Ford Taurus SE with the 3.0L Vulcan OHV engine. This model year has done away with the CCRM (Constant Control Relay Module), so the relays...


fuse #9 protects the 2 cooling fan relays.

It looks like the hgh speed cooling fan realy is in a thin box mounted sideways between the battery and fender.

It has high speed relay, autolamp relay, autolamp headlamp relay, horn relay, washer motor relay, wiper hi/lo relay, wiper park relay.

Section 03-03: Engine Cooling 1999 Taurus, Sable Workshop Manual
DESCRIPTION AND OPERATION Electrical System NOTE: With A/C ON, the cooling fan motors will run continuously. Cooling fan motors will not cycle ON and OFF with A/C clutch (2884) .

NOTE: An exception to this is when vehicle speed is over 61 km/h (38 mph) and coolant temperature is below 100°C (212°F), and A/C head pressure is below 1.71 MPA (250 psi). The cooling fan motors will then automatically shut off.

The cooling fan motors are mounted within a fan shroud (8146) behind the radiator (8005) .

Engine Cooling Fan Control CCRM Applications The PCM monitors certain parameters (such as engine coolant temperature, vehicle speed, A/C on/off status, A/C pressure, etc) to determine engine cooling fan needs. The PCM controls the fan operation through the Fan Control (FC) output (single speed fan applications) or the Low Fan Control (LFC) and High Fan Control (HFC) outputs as shown in Table 2. Although the fan control (FC), low speed fan control and high speed fan control relays are normally open relays, the FC/LFC circuit is wired through a voltage inverter inside the CCRM. The voltage inverter ensures that the PCM must turn on (ground) the FC/LFC output to turn the fan off. This is done so the cooling fan will operate in the event of an open FC/LFC circuit.

Stand-Alone Fan Control Relay Applications The PCM monitors certain parameters (such as engine coolant temperature, vehicle speed, A/C on/off status, A/C pressure, etc) to determine engine cooling fan needs. The PCM determines engine cooling fan control requirements and controls the fan operation through the Low Fan Control (LFC) and High Fan Control (HFC) outputs (Table 3).

Jun 29, 2009 | 1999 Ford Taurus

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