GM Service Manual Online
For 1990-2009 cars only

Your vehicle is equipped with a second battery. Refer to the following instructions when making use of it. After reading the following information, keep it with your owner's manual for future reference.

  1. Disconnect the positive (+) battery cable at the primary underhood battery.
  2. Remove one nut from the junction block (located just inboard from the primary battery on the radiator tie bar), and retain for use in step 3.
  3. Locate the lead from the auxiliary positive (+) battery cable and install to the junction block. Reinstall the nut from step 2. Torque to 10.0 ± 2.0 N·m.

  4. Object Number: 854277  Size: B4
  5. At the auxiliary (rear) battery, locate the short positive (+) battery cable.
  6. Remove the two nuts from the rear battery isolator posts and retain them for use in Step 8.
  7. Attach the double-crimped positive (+) terminal to the top post of the isolator.
  8. Attach the single terminal to the lower post of the isolator.
  9. Torque both nuts to 10.0 ± 2.0 N·m
  10. Affix the protective boots over the nuts.
  11. Secure the short auxiliary positive (+) battery cable to the auxiliary battery. Torque to 15.0 ± 5.0 N·m.
  12. Attach the negative (-) battery cable to the battery and frame. Torque at battery is 15.0 ± 5.0 N·m. Torque at frame is 10.0 ± 2.0  N·m.

  13. Object Number: 854274  Size: B4
  14. At the primary underhood battery, re-attach the positive (+) battery cable to the primary battery. Torque to 15.0 ± 5.0 N·m.

During vehicle usage, obtain 12 volt electrical power from the available end of the megafuse which is near the primary battery.