Pinpoint Test W: The Blower Motor is Inoperative - EMTC
Climate Control System
Pinpoint Tests
Pinpoint Test W: The Blower Motor is Inoperative - EMTC
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Voltage is supplied to the relay coil from Battery Junction Box (BJB) fuse 52 (5A) and relay switch contacts from BJB fuse 51 (40A). The coil receives ground from the HVAC module if any function selector position but OFF is selected. When the relay coil is grounded by the HVAC module, the relay is energized and voltage is delivered to the blower motor. Ground for the blower motor is provided from the blower resistor or the blower switch (in HI only). The blower resistor and blower switch are grounded.
- DTC B10AF:12 (Blower Fan Relay: Circuit Short to Battery) - the module senses excessive voltage on the relay coil ground circuit when the module is grounding the circuit for more than 2 seconds.
- DTC B10AF:13 (Blower Fan Relay: Circuit Open) - the module senses no voltage on the relay coil ground circuit when the module is grounding the circuit for more than 2 seconds.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor
- Blower motor relay
- HVAC module
PINPOINT TEST W: THE BLOWER MOTOR IS INOPERATIVE - EMTC
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W1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Are any DTCs present?
Yes
For B10AF:12, GO to W2.
For B10AF:13, CARRY OUT the blower motor relay component test.
If the relay tests OK, GO to W3.
No
GO to W5.
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W2 CHECK THE BLOWER MOTOR RELAY COIL SWITCHED GROUND CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Disconnect: HVAC Module - EMTC C294B.
- Ignition ON.
- Measure the voltage between blower motor relay socket pin 2, circuit CH123 (VT/GN) and ground.
- Is any voltage present?
Yes
REPAIR circuit CH123 (VT/GN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to W11.
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W3 CHECK THE BLOWER MOTOR RELAY COIL SUPPLY VOLTAGE
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Ignition ON.
- Measure the voltage between blower motor relay socket pin 1, circuit CBB52 (GN/WH) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to W4.
No
VERIFY Battery Junction Box (BJB) fuse 52 (5A) is OK. If OK, REPAIR circuit CBB52 (GN/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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W4 CHECK THE BLOWER MOTOR RELAY COIL SWITCHED GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module - EMTC C294A.
- Measure the resistance between blower motor relay socket pin 2, circuit CH123 (VT/GN) and HVAC module - EMTC C294A-11, circuit CH123 (VT/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to W11.
No
REPAIR circuit CH123 (VT/GN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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W5 CHECK THE HVAC MODULE BLOWER MOTOR RELAY OUTPUT
NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table or equivalent. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Ignition ON.
- Connect the 12-volt test light between blower motor relay socket pin 1, circuit CBB52 (GN/WH) and socket pin 2, circuit CH123 (VT/GN).
- Select PANEL on the HVAC controls.
- Does the test light illuminate?
Yes
GO to W6.
No
GO to W11.
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W6 CHECK THE BLOWER MOTOR RELAY SWITCH CONTACT VOLTAGE CIRCUIT FOR AN OPEN
- Measure the voltage between blower motor relay socket pin 3, circuit SBB51 (BU/RD) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to W7.
No
VERIFY Battery Junction Box (BJB) fuse 51 (40A) is OK. If OK, REPAIR circuit SBB51 (BU/RD) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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W7 CHECK THE BLOWER MOTOR RELAY
- Connect fused jumper lead between blower motor relay socket pin 3, circuit SBB51 (BU/RD) and socket pin 5, circuit CH402 (YE/GN).
- Does the blower motor operate?
Yes
INSTALL a new blower motor relay. TEST the system for normal operation.
No
GO to W8.
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W8 CHECK FOR GROUND TO THE BLOWER MOTOR
- Ignition OFF.
- Disconnect: Blower Motor C2004.
- Turn the blower motor switch to the HI position.
- Measure the resistance between blower motor connector C2004-2, circuit CH426 (YE/OG), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to W9.
No
GO to W10.
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W9 CHECK FOR VOLTAGE TO THE BLOWER MOTOR
- Connect: Blower Motor Relay.
- Ignition ON.
- Select PANEL on the HVAC controls.
- Measure the voltage between blower motor C2004-1, circuit CH402 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new blower motor. REFER to Climate Control Service and Repair. TEST the system for normal operation.
No
REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
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W10 CHECK THE BLOWER MOTOR GROUND CIRCUIT FOR AN OPEN
- Disconnect: HVAC Module - EMTC C294B.
- Measure the resistance between HVAC module - EMTC C294B-2, circuit CH426 (YE/OG), harness side and blower motor C2004-2, circuit CH426 (YE/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
REPAIR circuit GD138 (BK/WH) for an open. TEST the system for normal operation.
No
REPAIR circuit CH426 (YE/OG) for an open. TEST the system for normal operation.
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W11 CHECK THE HVAC MODULE CONNECTION
- Inspect the HVAC module connectors for:
- corrosion
- pushed-out terminals
- damaged terminals
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Enter the following diagnostic mode on the scan tool: Self-Test - HVAC Module.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new HVAC module. REFER to Climate Control Service and Repair. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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