What does it mean?
B1845 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Power Seat Recline Switch Circuit Malfunction .
Symptoms
- Seat back will not recline or return upright
- Recline works in only one direction
- Seat back moves by itself while driving
- Memory recall does not restore the backrest angle
- No motor noise when the recline switch is pressed
Likely causes
- Recline switch contacts worn or contaminated in the side trim switch pack
- Open or short in the recline signal wire under the seat
- Harness rubbed through where it crosses the seat frame or rail
- Liquid spilled onto the switch pack from the door pocket side
- Under-seat connector partly unplugged or with a corroded terminal
- Recline motor drawing abnormal current and disturbing the module input reference
- Seat module input failure
How to fix it
- Watch the recline switch status in live data while operating it both ways
- Unplug the switch pack and measure the contacts in rest and both actuated positions
- Inspect the harness at the seat frame and rails with the seat at full travel
- Back-probe the module input and confirm the expected voltage change
- Measure the recline motor current draw to rule out a binding mechanism
- Replace the switch pack when the contacts are open or intermittent
- Replace the seat module last and relearn the memory positions