What does it mean?
B1927 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Left Rear Window Control Circuit Low .
Symptoms
- Left rear window does not operate in one direction, or does not operate at all
- Window does not respond from either the rear switch or the driver master switch
- Fuse for the rear windows blows repeatedly
- Motor buzzes or clicks without moving the glass
- Window falls into the door or stops partway and will not close
Likely causes
- Control wire shorted to ground inside the left rear door or in its jamb boot
- Water entering through a damaged door membrane onto the motor or module connector
- Window regulator binding, or the motor seized so it overloads the output
- Loom chafed against the regulator rail or a sharp bracket inside the door
- Rear door window switch failed and holding the control line to ground
- Body or door module output driver failed shorted
- Damage after speaker, child lock or aftermarket accessory work in that door
How to fix it
- Check the fuse feeding the rear windows and confirm battery voltage before testing further
- Read the module codes and watch the output state in live data while operating the window from both switches
- Unplug the window motor and measure the control wire to ground with the module also disconnected; a low reading proves a wiring short
- If the wiring is clean, bench test the motor for a shorted winding and check the regulator for binding
- Peel back the door jamb boot and inspect the harness where it flexes, looking for crushed or bare conductors
- Substitute or measure the rear window switch to rule it out
- Replace the controlling module last, once wiring, switch and motor have all tested good