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Home >> Honda >> 2021 >> CR-V EX-L, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (HVAC System - Testing & Troubleshooting (Hybrid)) >> Troubleshooting >> PTC Heater Circuit Troubleshooting

PTC Heater Circuit Troubleshooting

WARNING: This page is about a different variant/trim than selected.

NOTE:  Do this troubleshooting procedure only if sent here by symptom troubleshooting index .

  1. Determine possible failure area (PTC heater, fuse)

    -1. Check the following fuses.

    Fuse No. C1-1
    No. C1-3

    Are the fuses OK?

    YES: PTC heater B

    Go to step 2.

    YES: PTC heater D

    Go to step 10.

    NO 

    Replace the fuse(s), and recheck. If the fuse blows again, repair a short in the No. C1-1 or No. C1-3 fuse circuit.

  2. PTC heater B relay check

    -1. Remove the PTC heater B relay from the under-hood fuse/relay box, and test it .

    Is the relay OK?

    YES 

    Go to step 3.

    NO 

    Replace the PTC heater B relay.

  3. Open wire check (GND line)

    -1. Disconnect the following connector.

    PTC heater core 5P connector

    -2. Measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PTC heater B relay: disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 PTC heater core 5P connector (female terminals) No. 1:
    Test point 2 Body ground
    GHH379234Courtesy of HONDA, U.S.A., INC.

    Is there 1.0 Ω or less?

    YES 

    The GND wire is OK. Go to step 4.

    NO 

    Check for an open in the GND wire. If the wires are OK, check for poor ground at G352.

  4. PTC heater B circuit check

    -1. Disconnect the following connectors.

    Climate control unit connector A (32P)

    -2. Connect terminals A and B with jumper wires.

    Terminal A Climate control unit connector A (32P) No. 22 
    Terminal B Body ground
    Terminal A PTC heater B relay 4P socket (female terminals) No. 1:
    Terminal B PTC heater B relay 4P socket (female terminals) No. 2:
    Terminal A PTC heater B relay 4P socket (female terminals) No. 3:
    Terminal B PTC heater B relay 4P socket (female terminals) No. 4:
    GHH379239Courtesy of HONDA, U.S.A., INC.

    -3. Turn the vehicle to the ON mode.

    -4. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    PTC heater B relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Climate control unit connector A (32P) No. 22: jumped to body ground
    PTC heater B relay 4P socket No. 1 and No. 2: jumped
    PTC heater B relay 4P socket No. 3 and No. 4: jumped
    Test point 1 PTC heater core 5P connector (female terminals) No. 5:
    Test point 2 Body ground
    GHH379241Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 5.

    NO 

    Go to step 6.

  5. PTC heater B check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Remove the jumper wires.

    -3. Test the PTC heater core .

    Is the PTC heater B OK?

    YES 

    Replace the climate control unit .

    NO 

    Replace the PTC heater core .

  6. Open wire check (A/C_PTC2 line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Remove the jumper wires.

    -3. Measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PTC heater B relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 PTC heater B relay 4P socket (female terminals) No. 2:
    Test point 2 PTC heater core 5P connector (female terminals) No. 5:
    GHH379244Courtesy of HONDA, U.S.A., INC.
    GHH379245Courtesy of HONDA, U.S.A., INC.

    Is there 1.0 Ω or less?

    YES 

    The A/C PTC2 wire is OK. Go to step 7.

    NO 

    Repair an open in the A/C_PTC2 wire.

  7. Open wire check (+B_A/C_PTC1 line)

    -1. Measure the voltage between these test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PTC heater B relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 PTC heater B relay 4P socket (female terminals) No. 1:
    Test point 2 Body ground
    GHH379247Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    The +B_A/C_PTC1 wire is OK. Go to step 8.

    NO 

    Repair an open in the +B_A/C_PTC1 wire.

  8. Open wire check (IG2_A/C line)

    -1. Turn the vehicle to the ON mode.

    -2. Measure the voltage between these test points 1 and 2.

    Test condition Vehicle ON mode
    PTC heater B relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 PTC heater B relay 4P socket (female terminals) No. 3:
    Test point 2 Body ground
    GHH379249Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    The IIG2_A/C wires are OK. Go to step 9.

    NO 

    Repair an open in the IG2_A/C wire.

  9. Open wire check (A/C_PTC2_RLY_CL- line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PTC heater B relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 Climate control unit connector A (32P) No. 22 
    Test point 2 PTC heater B relay 4P socket (female terminals) No. 4:
    GHH379251Courtesy of HONDA, U.S.A., INC.

    Is there 1.0 Ω or less?

    YES 

    Replace the climate control unit .

    NO 

    Repair an open in the A/C_PTC2_RLY_CL- wire.

  10. PTC heater D relay check

    -1. Remove the PTC heater D relay from the under-hood fuse/relay box, and test it .

    Is the relay OK?

    YES 

    Go to step 11.

    NO 

    Replace the PTC heater D relay.

  11. Open wire check (GND line)

    -1. Disconnect the following connector.

    PTC heater core 5P connector

    -2. Measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PTC heater D relay: disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 PTC heater core 5P connector (female terminals) No. 2:
    Test point 2 Body ground
    GHH379253Courtesy of HONDA, U.S.A., INC.

    Is there 1.0 Ω or less?

    YES 

    The GND wire is OK. Go to step 12.

    NO 

    Check for an open in the GND wire. If the wires are OK, check for poor ground at G352.

  12. PTC heater D circuit check

    -1. Disconnect the following connectors.

    Climate control unit connector A (32P)

    -2. Connect terminals A and B with a jumper wires.

    Terminal A Climate control unit connector A (32P) No. 23 
    Terminal B Body ground
    Terminal A PTC heater D relay 4P socket (female terminals) No. 1:
    Terminal B PTC heater D relay 4P socket (female terminals) No. 2:
    Terminal A PTC heater D relay 4P socket (female terminals) No. 3:
    Terminal B PTC heater D relay 4P socket (female terminals) No. 4:
    GHH379258Courtesy of HONDA, U.S.A., INC.

    -3. Turn the vehicle to the ON mode.

    -4. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    PTC heater B relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Climate control unit connector A (32P) No. 23: jumped to body ground
    PTC heater D relay 4P socket No. 1 and No. 2: jumped
    PTC heater D relay 4P socket No. 3 and No. 4: jumped
    Test point 1 PTC heater core 5P connector (female terminals) No. 3:
    Test point 2 Body ground
    GHH379260Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 13.

    NO 

    Go to step 14.

  13. PTC heater D check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Remove the jumper wires.

    -3. Test the PTC heater core .

    Is the PTC heater D OK?

    YES 

    Replace the climate control unit .

    NO 

    Replace the PTC heater core .

  14. Open wire check (A/C_PTC4 line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Remove the jumper wires.

    -3. Measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PTC heater D relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 PTC heater D relay 4P socket (female terminals) No. 2:
    Test point 2 PTC heater core 5P connector (female terminals) No. 3:
    GHH379263Courtesy of HONDA, U.S.A., INC.
    GHH379264Courtesy of HONDA, U.S.A., INC.

    Is there 1.0 Ω or less?

    YES 

    The A/C_PTC4 wire is OK. Go to step 15.

    NO 

    Repair an open in the A/C_PTC4 wire.

  15. Open wire check (+B_A/C_PTC3 line)

    -1. Measure the voltage between these test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PTC heater D relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 PTC heater D relay 4P socket (female terminals) No. 1:
    Test point 2 Body ground
    GHH379266Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    The +B_A/C_PTC3 wire is OK. Go to step 16.

    NO 

    Repair an open in the +B_A/C_PTC3 wire.

  16. Open wire check (IG2_A/C line)

    -1. Turn the vehicle to the ON mode.

    -2. Measure the voltage between these test points 1 and 2.

    Test condition Vehicle ON mode
    PTC heater D relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 PTC heater D relay 4P socket (female terminals) No. 3:
    Test point 2 Body ground
    GHH379268Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    The IG2_A/C wires are OK. Go to step 17.

    NO 

    Repair an open in the IG2_A/C wire.

  17. Open wire check (A/C_PTC4_RLY_CL- line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PTC heater D relay: disconnected
    Climate control unit connector A (32P): disconnected
    PTC heater core 5P connector: disconnected
    Test point 1 Climate control unit connector A (32P) No. 23 
    Test point 2 PTC heater D relay 4P socket (female terminals) No. 4:
    GHH379270Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Replace the climate control unit .

    NO 

    Repair an open in the A/C_PTC4_RLY_CL- wire.

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