Pinpoint Test L: The Blower Motor Does Not Operate Correctly
Climate Control System
Pinpoint Test L: The Blower Motor Does Not Operate Correctly
Refer to Wiring Diagrams Set 54, Manual Climate Control System for schematic and connector information. Electrical Diagrams
Normal Operation
The blower motor is provided a ground through the part of the blower resistor in LO, MED-LO and MED-HI blower setting. Part of the resistor is grounded by the blower motor switch depending on the setting. In HI, the blower motor is grounded directly through the blower motor switch. The blower switch is provided a ground.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blower motor switch
- Blower motor resistor
PINPOINT TEST L : THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY
L1 CHECK THE BLOWER MOTOR OPERATION
- Ignition ON.
- Turn the function selector switch to the FLOOR position.
- Select all blower speed positions.
Does the blower motor operate in any position?
Yes
If the blower motor does not operate in HI setting only, GO to L2.
If the blower motor does not operate in LO, MED-LO or MED-HI setting only, CARRY OUT the Blower Motor Resistor component test. If the resistor tests OK, GO to L3. Component Tests and General Diagnostics
For all other symptoms, GO to L4.
No
GO to Pinpoint Test K. Pinpoint Test K: The Blower Motor Is Inoperative
L2 CHECK THE BLOWER MOTOR HI CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C271.
- Disconnect: Blower Motor C2004.
- Measure the resistance between blower motor switch C271-6, circuit 31S-FA33 (BK/OG), harness side and blower motor C2004-2, circuit 31S-FA18 (BK/RD), harness side.
Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
REPAIR circuit 31S-FA18 (BK/RD) or 31S-FA33 (BK/OG) for an open. TEST the system for normal operation.
L3 CHECK THE BLOWER MOTOR SWITCH
NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning. 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 Resistor C293.
- For LO inoperative
For LO inoperative: With the blower motor switch in the LO speed position, connect a 12-volt test light between blower motor resistor C293-1, circuit 31S-FA1 (BK/BU), harness side and blower motor resistor C293-3, circuit 31S-FA30 (BK/WH), harness side.
- For MED-LO inoperative
For MED-LO inoperative: With the blower motor switch in the MED-LO speed position, connect a 12-volt test light between blower motor resistor C293-1, circuit 31S-FA1 (BK/BU), harness side and blower motor resistor C293-2, circuit 31S-FA31 (BK/YE), harness side.
- For MED-HI inoperative
For MED-HI inoperative: With the blower motor switch in the MED-HI speed position, connect a 12-volt test light between blower motor resistor C293-1, circuit 31S-FA1 (BK/BU), harness side and blower motor resistor C293-4, circuit 31S-FA32 (BK/BU), harness side.
Does the test light illuminate?
Yes
INSTALL a new blower motor resistor. TEST the system for normal operation.
No
CARRY OUT the Blower Motor Switch component test. If the switch tests OK, REPAIR circuit 31S-FA30 (BK/WH), 31S-FA31 (BK/YE) or 31S-FA32 (BK/BU) for an open. TEST the system for normal operation. Component Tests and General Diagnostics
L4 CHECK THE BLOWER MOTOR SWITCH TO RESISTOR CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Blower Motor Resistor C293.
- Disconnect: Blower Motor Switch C271.
- Measure the resistance between ground and blower motor switch:
- C271-1, circuit 31S-FA30 (BK/WH), harness side.
- C271-3, circuit 31S-FA31 (BK/YE), harness side.
- C271-5, circuit 31S-FA32 (BK/BU), harness side.
Are the resistances greater than 10,000 ohms?
Yes
GO to L5.
No
REPAIR circuit 31S-FA30 (BK/WH), 31S-FA31 (BK/YE) or 31S-FA32 (BK/BU) for a short to ground. TEST the system for normal operation.
L5 CHECK THE BLOWER MOTOR SWITCH TO RESISTOR CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between blower motor switch:
- C271-1, circuit 31S-FA30 (BK/WH), harness side and C271-3, circuit 31S-FA31 (BK/YE), harness side.
- C271-1, circuit 31S-FA30 (BK/WH), harness side and C271-5, circuit 31S-FA32 (BK/BU), harness side.
- C271-3, circuit 31S-FA31 (BK/YE), harness side and C271-5, circuit 31S-FA32 (BK/BU), harness side.
Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
REPAIR circuit 31S-FA30 (BK/WH), 31S-FA31 (BK/YE) or 31S-FA32 (BK/BU) for a short together. TEST the system for normal operation.