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Power Rear Headrest Acura RL II

Seats 9 illustrations ~990 words

Scheme 84

Scheme 84: Component Location Index
Scheme 84: Component Location Index

Scheme 85

Scheme 85: Circuit Diagram
Scheme 85: Circuit Diagram

DTC B1848: Rear Headrest Switch Signal Error

Note. If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Scheme 86

Scheme 86: DTC B1848: Rear Headrest Switch Signal Error
Scheme 86: DTC B1848: Rear Headrest Switch Signal Error

Scheme 87

Scheme 87
Scheme 87

Scheme 88

Scheme 88
Scheme 88

Scheme 89

Scheme 89
Scheme 89
  1. Clear the DTCs with the HDS.
  2. Turn the ignition switch OFF, and then back ON (II).
  3. Retract the rear headrests with the headrest switch.
  4. Check for DTCs with the HDS. Is DTC B1848 indicated? YES -Go to step 5. NO -Intermittent failure, the rear headrest system is OK at this time. Check for loose or poor connections.
  5. Turn the ignition switch OFF.
  6. Disconnect power seat control unit connector A (40P).
  7. Disconnect the roof console 28P connector.
  8. Check for continuity between body ground and power seat control unit connector A (40P) terminals No. 1 and No. 22 individually. Is there continuity? YES -Repair a short to ground in the wire. NO -Go to step 9.
  9. Check for continuity between power seat control unit connector A (40P) terminals No. 1 and No. 22. Is there continuity? YES -Repair a short in the wire. NO -Go to step 10.
  10. Reconnect the 28P connector to the roof console.
  11. Check for continuity between power seat control unit connector A (40P) terminals No. 1 and No. 22 without pressing the headrest switch. Is there continuity? YES -Faulty headrest switch, replace the roof console (see «ROOF CONSOLE REPLACEMENT»(/acura/rl/ii-2004-2008/remont/interiorillumination-lights/#interior-lights) ). NO -Go to step 12.
  12. Disconnect the roof console 28P connector.
  13. Check for continuity between roof console 28P connector terminals No. 9 and No. 10 and roof console body ground. Is there continuity? YES -Faulty headrest switch, replace the roof console (see «ROOF CONSOLE REPLACEMENT»(/acura/rl/ii-2004-2008/remont/interiorillumination-lights/#interior-lights) ). NO -Go to the power seat control unit input test (see «CONTROL UNIT INPUT TEST»(/acura/rl/ii-2004-2008/remont/seats/#power-rear-headrest__control-unit-input-test) ).

Control Unit Input Test

Note. Before troubleshooting, troubleshoot the multiplex integrated control system first using B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Scheme 90

Scheme 90: Control Unit Input Test
Scheme 90: Control Unit Input Test
  1. Turn the ignition switch OFF.
  2. Remove the mounting bolts from the driver's power seat (see «FRONT SEAT REMOVAL/INSTALLATION»(/acura/rl/ii-2004-2008/remont/seats/#seats__front-seat-removalinstallation) ) and carefully tip the seat back. NOTE: Be careful not to scratch the interior trim.
  3. Disconnect the 40P connector (A) and 18P connector (B) from the power seat control unit (C).
  4. Inspect the connector and socket terminals to be sure they are all making good contact. If the terminals are bent, loose or corroded, repair them as necessary and recheck the system. If the terminals look OK, go to step 5.
  5. With the power seat control unit connectors still disconnected, make these input tests at the connectors. If any test indicates a problem, find and correct the cause, then recheck the system. If all the input tests prove OK, go to step 6. WIRE CAVITY REFERENCE CHART Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained A1 . A22 BRN . YEL/WHT Headrest switch ON (pressed) Check for continuity between the A1 and A22 terminals: There should be continuity. Faulty headrest switch An open in the wire A short in the wire Headrest switch OFF (released) Check for continuity between the A1 and A22 terminals: There should be no continuity. B12 . B5 BLK . RED Under all conditions Connect the B1 and B12 terminals, and B5 and A9 terminals momentarily: The headrest actuators should work. Faulty headrest actuator An open in the wire
  6. Reconnect the connectors A (40P) and B (18P) to the control unit, and make these input tests at the connectors. If any tests indicate a problem, find and correct the cause, then recheck the system. If all tests prove OK, the power seat control unit must be faulty; replace it. WIRE CAVITY REFERENCE CHART Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained A9 BLK Under all conditions Measure the voltage to ground: There should be less than 0.5 V. Poor ground (G601) An open in the wire A35 BLK/YEL Ignition switch ON (II) Measure the voltage to ground: There should be battery voltage. Blown No. 21 (10A) fuse in the driver's under-dash fuse/relay box An open in the wire A37 BLU Under all conditions Measure the voltage to ground: There should be battery voltage. Blown No. 15 (40A) fuse in the under-hood fuse/relay box Blown No. 7 (10A) fuse in the driver's under-dash fuse/relay box An open in the wire B1 RED Under all conditions Measure the voltage to ground: There should be battery voltage. Blown No. 20 (40A) fuse in the under-hood fuse/relay box Blown No. 16 (20A) fuse in the driver's under-dash fuse/relay box An open in the wire B8 BLU Under all conditions Measure the voltage to ground: There should be battery voltage. Blown No. 20 (40A) fuse in the under-hood fuse/relay box Blown No. 14 (20A) fuse in the driver's under-dash fuse/relay box An open in the wire

Scheme 91

Scheme 91: Headrest Switch Test
Scheme 91: Headrest Switch Test
  1. Remove the roof console (see «ROOF CONSOLE REPLACEMENT»(/acura/rl/ii-2004-2008/remont/interiorillumination-lights/#interior-lights) ).
  2. Disconnect the 28P connector (A) from the roof console (B).
  3. Check for continuity between the roof console 28P connector No. 9 and No. 10 terminals. There should be continuity when the headrest switch (C) is pressed. There should be no continuity when the headrest switch is released.
  4. If the continuity is not as specified, replace the roof console (see «ROOF CONSOLE REPLACEMENT»(/acura/rl/ii-2004-2008/remont/interiorillumination-lights/#interior-lights) ).

Scheme 92

Scheme 92: Headrest Actuator Test
Scheme 92: Headrest Actuator Test
  1. Remove the rear seat headrest covers (see «REAR SEAT HEAD RESTRAINT COVER/PAD REPLACEMENT»(/acura/rl/ii-2004-2008/remont/seats/#seats__rear-seat-head-restraint-coverpad-replacement) ).
  2. Disconnect the 2P connector (A) from the headrest actuator (B).
  3. Check the actuator by connecting battery power to the No. 2 terminal and ground the No. 1 terminal momentarily. The actuator should work.
  4. If the actuator does not work, replace the actuator.

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