Door lock works with keyless entry functions, but does not answer back, or room light does not illuminate (BCM)

1. Door lock works with keyless entry functions, but does not answer back, or room light does not illuminate diagnostics

1. Pre-check and visual inspection

Verify that the battery voltage is normal.
If the battery voltage is not normal, charge or replace the battery.

Verify that the fuses are normal.
If an abnormal condition such as a blowout is found in a fuse, inspect or repair the cause of the abnormal condition before replacing the fuse.

Confirm that the ground point is normal.
Repair and clean the ground point if improperly installed or significantly dirty.

Verify that the harness connectors are normal.
Inspect for poor connections at the connectors, worn or bent harnesses, or split wires inside the harness shorted to other circuits.

Check for any interference from aftermarket electronic components such as two-way radios or lights.
Remove any aftermarket electronic components or turn OFF the power to ensure that there is no influence on inspections or operations.

2. Components inspection

Check the BCM.
Observe the DTC information, and inspect the BCM if a malfunction is found.

Check the turn signal light.
If a malfunction is found in the turn signal light, replace it.

3. Circuit inspection

Check the following circuits for an open circuit, short to the power supply, short to ground, and high resistance.
If a malfunction is found in the circuit, repair or replace the applicable circuit.

Note

  • Check the symptoms and inspect only the circuit related to the malfunctioning light.
  • Between the BCM and the dome light, and between the BCM and the map light.
  • Front right: between the BCM and the front turn signal light (right)
  • Front right GND: between the front turn signal light (right) and the engine room ground terminal
  • Front left: between the BCM and the front turn signal light (left)
  • Front left GND: between the front turn signal light (left) and the engine room ground terminal
  • Right side: between the BCM and the side turn signal light (right)
  • Right side GND: between the side turn signal light (right) and the engine room ground terminal
  • Left side: between the BCM and the side turn signal light (left)
  • Left side GND: between the side turn signal light (left) and the engine room ground terminal
  • Rear right: between the BCM and the rear turn signal light (right)
  • Rear right GND: between the rear turn signal light (right) and the engine room ground terminal
  • Rear left: between the BCM and the rear turn signal light (left)
  • Rear left GND: between the rear turn signal light (left) and the engine room ground terminal
Copyright Mazda Motor Corporation. All rights reserved.