What does it mean?
B1407 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Front Right Audio Speaker Output Circuit Open .
Symptoms
- Front right speaker is silent while the rest of the system still plays normally
- Sound stage pulls to the left and the balance/fade adjustment no longer evens it out
- Crackling or intermittent output from that corner, often changing as the door is opened or slammed
- Volume has to be turned up to compensate, which makes the remaining speakers distort
- Stored audio fault, and on some systems a service message on the display
Likely causes
- Broken conductor inside the front right door jamb boot, where the wires flex every time the door is opened
- Open or burnt voice coil in the front right speaker itself
- Backed-out, spread or corroded terminal in the speaker connector or the door bulkhead connector
- Water running down inside the door skin, corroding the speaker pins green
- Aftermarket radio, amplifier or speaker adapter that leaves the factory output unterminated
- Failed output stage inside the audio amplifier or the head unit
How to fix it
- Read and record the stored codes, then clear and retest so you know whether the fault is current or historic
- Remove the front right door trim and inspect the speaker connector and the rubber door boot for broken, green or backed-out terminals
- Measure the voice coil directly at the speaker terminals; a serviceable unit reads a few ohms, an open one reads infinite
- Check continuity of both speaker wires from the amplifier connector to the speaker while flexing the door harness by hand
- Repair any break inside the door boot with soldered and sealed joints rather than an exposed crimp
- Replace the speaker if its coil is open, and only then consider the amplifier or head unit
- Remove or correctly rewire any aftermarket audio hardware that loads the factory output improperly