P21-1049-2201 | Genuine Paccar® 2.1M Drivers Door Control

Kenworth T680
Other newer (mid-2010s+) PACCAR trucks with 2.1M electrical architecture / door modules

Turns the interior lights on when the door opens and off when the door closes.

2. Door Ajar Warning

Sends a signal to the dashboard to show a “Door Ajar” warning if a door isn’t fully shut.

3. Power Door Locks

Controls the lock/unlock mechanism when you:

• Press the lock/unlock button

• Use the key fob

• Use keyless entry

4. Power Windows (on some models)

Regulates window movement from the door panel switch.

5. Alarm System

Lets the alarm know if someone opens the door without authorization.

1. Dome Lights Don’t Turn On or Off

• Interior lights stay on all the time, even with the door closed

• Interior lights never turn on when you open the door
  This points to a failing door ajar switch.

2. “Door Ajar” Warning Stays On

• Dash shows a door open warning even when the door is fully closed

• Alarm may not arm because the car thinks a door is open
  This means the door switch isn't sending the correct signal.

3. Power Windows Don’t Work

• Pressing the window button does nothing

• Window works only from the driver’s switch, not the door’s switch

• Window moves intermittently
  This usually indicates a bad window switch.

4. Power Door Locks Don’t Respond

• Lock/unlock button does nothing

• Locks work only with the key fob but not the door switch

• Locks work sometimes, then stop
  A failing door lock switch can cause this.

5. Alarm Goes Off Unexpectedly

If the door switch sends false “open” signals, the alarm thinks a door has been opened illegally.

6. Door Mirrors Don’t Adjust (if switch is in door)

• Mirror adjustment switch becomes unresponsive or intermittent.

7. Clicking, Sticking, or No “Feel” in the Switch

• Button feels loose

• Sticks when pressing

• No clicking sensation
  Indicates worn-out internal contacts.