What does it mean?
B1604 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Right Solar Sensor Circuit Low .
Symptoms
- Security indicator is completely dead, with no flash at key on and no flash when the alarm arms
- The driver has no way to confirm the vehicle is armed before walking away
- All other cluster warning lamps behave normally
- The code stays current and does not clear with a key cycle
- On the sensor variant, the passenger side blows colder than commanded in sunlight
Likely causes
- Theft indicator bulb or LED failed open
- Cluster connector not fully seated after dash work, or a terminal backed out of the housing
- Broken wire between the module and the cluster
- Corroded terminal in the indicator circuit connector
- Open trace or failed driver on the cluster circuit board
- Module output stage open internally
- On applications where this code refers to climate control, a right side solar load sensor circuit reading low from a short to ground or a shorted sensor
How to fix it
- Run the module output test for the indicator and watch whether the cluster responds at all
- Check the bulb or LED first, since an open lamp is the simplest cause of this code
- Back-probe the indicator circuit at the module and check continuity through to the cluster pin
- Inspect the cluster connector for a pushed-back terminal, common after previous dash or radio work
- Verify the cluster power and ground before condemning the board
- Repair the wire or replace the lamp; leave the cluster and the module for last
- On the sensor variant, back-probe the right sensor, compare its voltage with specification and check the harness for a short to ground