2011-2016 Chevy/GMC Duramax LML | SOTF Switch

For your 2011–2016 GM LML 6.6L Duramax SOTF switch install, the switch wires will go to the gray J3 ECM connector.

For the common yellow/black LML switch:

Yellow wire → J3 gray connector, pin 11
Black wire → J3 gray connector, pin 35

Step-by-step:

1. Turn the key off and disconnect both negative battery cables.

2. Mount the switch inside the cab in a spot that is easy to reach, usually the lower dash/knee panel area. Make sure there is clearance behind the panel before drilling.

3. Route the yellow and black switch wires through the driver-side firewall, usually through the hood latch cable grommet. Use the supplied wire loom and keep the wiring away from heat, sharp edges, steering parts, and moving parts.

4. Locate the ECM on the driver side of the engine bay. Remove the plastic ECM cover/shield.

5. Find the gray J3 ECM plug. It is typically the gray ECM connector closest to the firewall.

6. Unlock and unplug the gray J3 connector from the ECM. Slide the lock tab out, release the connector, and rotate the lever to remove the plug.

7. Open the gray connector housing carefully. Remove the connector covers so you can access the pin cavities.

8. Locate pin 11 and pin 35. These locations may have plastic filler plugs in them. Carefully remove the plastic filler pins if present.

9. Insert the yellow switch terminal into pin 11 and the black switch terminal into pin 35. Make sure the terminals are facing the correct direction and fully lock into place. Lightly tug each wire to confirm it is seated.

10. Reinstall the connector covers and make sure the new terminals do not push back out.

11. Plug the gray J3 connector back into the ECM and make sure the connector is fully locked. Reinstall the ECM cover/shield.

12. Reconnect both negative battery cables.

13. Turn the key on and check the switch operation in the EZ LYNK app. Watch the switch position/DSP/SOTF-related PID and rotate the switch from 1–5. The value should change as the knob is turned.

14. The switch will only work after the correct SOTF switchable tune file is flashed to the truck. If a single-power tune is installed, the switch will not change power levels.

When flashing, keep a good battery charger connected, keep the phone/tablet close to the Auto Agent, keep the app open, and follow all EZ LYNK key-cycle prompts exactly.