Just to add a little on this diagnoses i would see if you have any fan code's here is the trouble tree for fans staying wrenchtech is right though remove the relay's one at a time and see if the fan's stop to see if there is a faulty relay.I posted a diagram showing you where the three relay's are the second diagram that show's the front of a vue the relay is call out number 3.Here is the trouble tree let me know what you find.
Cooling Fan Always On (3.5L)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. See: Testing and Inspection\Initial Inspection and Diagnostic Overview\Diagnostic Starting Point - Vehicle
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Circuit/System Description
The powertrain control module (PCM) commands the fans ON in high speed or low speed. In low speed, the fans are configured in series. In high speed, the fans are configured in parallel.
In low speed operation, the PCM applies ground to the coil side of the low speed relay. Voltage is applied directly to the left cooling fan through the switch side of the low speed relay. The right fan is connected in series to the left fan through the de-energized series/parallel relay so that both fans operate at low speed.
In high speed operation, the PCM applies a ground to the coil side of the low speed relay, the series/parallel relay, and the high speed relay. Voltage is applied directly to the right cooling fan through the switch side of the high speed relay. The left cooling fan obtains voltage through the low speed relay and ground through the series/parallel relay.
When the PCM is commanding a fan relay ON, the voltage of the control circuit should be low, near 0 volts. When the PCM is commanding a fan relay OFF, the voltage of the control circuit should be high, near battery voltage. If the PCM detects that the actual voltage of the relay control circuit is different than the expected voltage, DTC P0480 or P0481 will set and the affected PCM driver will be disabled.
Reference Information
Schematic Reference
Engine Cooling Schematics
Connector End View Reference
* Cooling System Component Views
* Cooling System Connector End Views
* Powertrain Control Module Connector End Views
Description and Operation
Cooling Fan Description and Operation
Electrical Information Reference
* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
* Scan Tool Data List
* Scan Tool Data Definitions
* Scan Tool Output Controls
Circuit/System Verification
1. Verify that the following DTCs are not set: P0480, P0481.
o If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle. See: Powertrain Management\Computers and Control Systems\Testing and Inspection\Diagnostic Trouble Code Descriptions\Diagnostic Trouble Code (DTC) List - Vehicle
2. Ignition ON, verify with a scan tool that the PCM is not commanding fan activation.
3. Ignition ON, observe that the fans are not activated.
Circuit/System Testing
1. Ignition OFF, disconnect the relays.
2. Ignition ON, observe that the fans are not activated.
o If the fans are not activated, replace the faulty relay.
o If a fan is activated, test the fan voltage supply circuits for a short to voltage.
Repair Instructions
* Cooling Fan and Shroud Replacement (L61) Cooling Fan and Shroud Replacement (L66) Cooling Fan and Shroud Replacement (LAT)
* Engine Cooling Fan Replacement (L66)
* Powertrain Control Module Replacement
Repair Verification
1. Ignition ON, verify with a scan tool that the PCM is not commanding fan activation.
2. Ignition ON, observe that the fan is not activated.
Images (Click to enlarge)
Jan 20, 2011 at 1:17 AM
