To replace this bulb: 1. Open the trunk.
2. Remove the trunk trim and pull back fastener.
3. Disconnect the wiring harness by lifting up on the tab to release and pull it straight out.
4. Turn the bulb socket counterclockwise and pull it straight out of the taillamp assembly.
5. Pull the old bulb straight out of the bulb socket.
6. Push the new bulb straight into the bulb socket until it clicks.
7. Push the bulb socket into the taillamp assembly and turn it clockwise to lock it into place.
8. Push the wiring harness straight into the bulb socket and push down on the tab.
9. Reinstall the trunk trim and fastener.
Chevrolet Cobalt Service & Repair Manual. Relearn
Initialization Sequence
The EBCM performs one initialization
test each ignition cycle. The initialization of the EBCM occurs when the
EBCM detects the there is a minimum of 500 RPM from the ECM by means of
a serial data message and the stop lamp switch is not applied. The initial ...